CBSE Board Last Year Papers

By | January 7, 2019

Class XII Last Year Paper

Click Here To View Chemistry Last Year Paper 2018

  • Question 1
    • Write the coordination number and oxidation state of Platinum in the
      complex [Pt (en)2Cl2].   (1 Marks)
  • Solution
    • Let oxidation state be x
      Now we know total charge on  [Pt (en)2Cl2] is zeroCharge on [Pt (en)2Cl2] = 0
      Also (en)2 has zero charge
      [ x + 2(0) +2(-1)]=0  (  Since Cl has -1 Charge ) x +0 -2=0
      x-2=0
      x=22
  • Question 2
    • Analysis shows that FeO has a non-stoichiometric composition with formula

      Fe

      0

      95


      O

      Give reason. (1 Marks)

  • Solution
    • Since FeO undergo the oxidation of

      Fe

      +
      2


      to


      Fe

      +
      3


      effectively replacing a small portion of


      Fe

      +
      2



      with two thirds their number of


      Fe

      +
      3


      . Thus FeO became non-stoichiometric compound and the formula is written as ,


      Fe

      (
      1

      x
      )


      O

      Where X lies between 0 to 95

  • Question 3
    • Out of chlorobenzene and benzyl chloride, which one gets easily hydrolysed
      by aqueous NaOH and why?
  • Solution
    • Benzyl chloride gets easily hydrolyzed by aq. NaOH.
      Chloro-benzene has partial double bond character due to resonance, thus it is very hard to break the bond. Thus chloro-benzene does not get hydrolyzed under normal conditions. But if appropriate temperature and pressure are provided it gets hydrolyzed.
  • Question 4
    • Write the IUPAC name of the following:  (1 Marks)
  • Solution
    • 3,3 dimethylpentan-2-ol.
  • Question 5

    • CO

      (
      g
      )


      and


      H

      2
       
      (
      g
      )


      react to give different products in the presence of different catalysts. Which ability of the catalyst is shown by these reactions?  (1 Marks)

  • Solution
    • Let us see it by two example Example 1
      • If CO and H2 react in the presence of Ni (nickel) as catalyst the product is methane.
    • Example 2
      • If CO and H2 react in the presence of Cu (copper) as catalyst the product formed is methanol.
  • Question 6
    • Among the hydrides of Group-15 elements, which have the [2] (a) Lowest boiling point?
      (b) Maximum basic character?
      (c) Highest bond angle?
      (d) Maximum reducing character?   (2 Marks)
  • Solution
    • a) PH3 has Lowest boiling point
      b) NH3 has Maximum basic character
      c) NH3 has Highest bond angle
      d) NH3 Maximum reducing character
  • Question 7
    • Calculate the freezing point of a solution containing 60 g of glucose (Molar mass = 180g

      mol


      1


      ) in 250 g of water. (


      K
      f

      of water = 1.86 K kg


      mol


      1


      )  (2 Marks)

  • Solution
    • Given Weight of water 

      W
      1

      =250 gWeight of glucose


      W
      2

      = 60 g
      Molar Mass


      M
      2

      =180 g


      mol


      1



      K
      f

      of water = 1.86 K kg


      mol


      1


      Now we know



      T
      f


      =




      K

      f
       


       
      ×
       
       

      W

      2
       


       
      ×
       
      1000



      M
      2

      ×

      W
      1



      =



      1
      .
      86
       
      ×
      60
      ×
      1000


      180
      ×
      250


      = 2.48
      Now



      T
      f

      =


      T
      0


      f
       



       

      T
      f

      =273.15 – 2.48
      Hence


      T
      f

      =270.67 K

  • Question 8
    • How do you convert the following?
      (a) Ethanal to Propanone
      (b) Toluene to Benzoic acid OR Account for the following:
      (a) Aromatic carboxylic acids do not undergo Friedel-Crafts reaction.
      (b)  value of 4-nitrobenzoic acid is lower than that of benzoic acid.     (2 Marks)
  • Solution
    • (a) (b) OR(a) This is due to electron present in withdrawing                 group of carboxylic acid which make  aromatic               ring electron deficient
      (b) It is due to e withdrawing nature of –NO2 attach         at the para position of Benzene in benzoni due to           which it loses H+ ion increases and acidic                         character increases.
  • Question 9
    • Complete and balance the following chemical equations: (2 Marks)
  • Solution
  • Question 10
    • For the reaction The rate of formation of  Calculate the rate of of disappearance of 
  • Solution
    • We HaveA rate of formation of  NO2  
  • Question 11
    • (a) Identify the chiral molecule in the following pair: (b) Write the structure of the product when                            chlorobenzene is treated with methyl chloride in            the presence of sodium metal and dry ether.
      (c) Write the structure of the alkene formed by                      dehydrohalogenation of 1-bromo                                        methylcyclohexane with alcoholic
      KOH.                                                  (3 Marks)
  • Solution
    • (a) (b) (c)
  • Question 12
    • A first order reaction is 50% completed in 40 minutes at 300 K and in 20
      minutes at 320 K. Calculate the activation energy of the reaction.
      (Given: log 2 = 0.3010, log 4 = 0.6021, R = 8.314 JK-1 mol-1)
  • Solution
    • Given    = 40
      For first half
  • Question 13
    • An element X’ (At. mass a 40 g mol-1) having f.c.c. structure, has unit cell
      edge length of 400 pm. Calculate the density of ‘X’ and the number of unit
      cells in 4 g of ‘X’. (NA = 6.022 x 1023 mol-1)
  • Solution
    • We have givenZ (No. of moles per unit ) = 4 g
      M (Molar mass)                  =40 g /mol
      a (edge )                                =400 pm (  cm)                                        = Avogadro constantNow Know Density of unit cell is
  • Question 14
    • Give reasons for the following:
      (a)Measurement of osmotic pressure method is preferred for the
      determination of molar masses of macromolecules such as proteins and
      polymers.
      (b)Aquatic animals are more comfortable in cold water than in warm water.
      (c) Elevation of boiling point of 1 M KCl solution is nearly double than that
      of 1 M sugar solution.                               (3 Marks)
  • Solution
    • (a) Osmotic pressure is fine at room temp, no special           arrangements are required and it depends on                 molarity whereas all other colligative properties             depend on molality and aslo Values of other                  colligative properties are very small that a small            error can account to large difference
      (b) As high temperature rises solubility of oxygen                decreases . So Aquatic species respirate more                  comfortably in cold water than in warm.
      (c) As colligative property depends only on number of       particle and KCl as electrolyte will produce double
      number of particle of sugar        (3 Marks)
  • Question 15
    • What happens when
      (a)a freshly prepared precipitate of Fe(OH)3 is shaken with a small amount
      of FeCl3 solution?
      (b)persistent dialysis of a colloidal solution is carried out?
      (c) an emulsion is centrifuged?
  • Solution
    • (a) Peptization occurs due to which colloidal solution         of Fe(OH)3 is formed
      (b) Dialysis a colloidal dispersion gets coagulated                 on persistent
      (c) Two liquid will separate on centrifugation of                    emulsion                                         (3 Marks)
  • Question 16
    • Write the chemical reactions involved in the process of extraction of Gold. Explain the role of dilute NaCN
      and Zn in this process.                       (3 Marks)
  • Solution
    • Gold is leached with a dilute solution of NaCN in the presence of air (For O2) from which the metal is
      obtained later by replacement.
  • Question 17
    • (A), (B) and (C) are three non-cyclic functional isomers of a carbonyl compound with molecular formula Isomers (A) and (C) give positive Tollen’s test whereas isomer (B) does not give Tollen’s test but gives positive Iodoform test. Isomers (A) and (B) on reduction with Zn(Hg)/conc. HCl give the same product (D).(a) Write the structures of (A), (B), (C) and (D).(b)Out of (A), (B) and (C) isomers, which one is least           reactive towards addition of HCN?
  • Solution
    • (b) (B) will be least reactive as it contain ketone as                 functional group and ketones are less reactive                 than aldehyde towards nucleophilic addition                  reaction
  • Question 18
    • (a) Why is bithional added to soap?
      (b) What is tincture of iodine? Write its one use.
      (c) Among the following, which one acts as a food
      preservative? Aspartame, Aspirin, Sodium                      Benzoate, Paracetamol
  • Solution
    • (a) Bithional helps to reduce odour produced by                  bacterial decomposition of organic matter
      on the skin
      (b) It is almost  2-3% iodine of alcohol water and it
      is used as antiseptic and applied on minor cuts
      ,scraps and burns to prevent infection
      (c) Sodium Benzoate
  • Question 19
    • (a) Write the formula of the following coordination             compound : iron(III) hexacyanoferrate(II)
      (b) What type of isomerism is exhibited by the                      complex (Co (NH3)5Cl)SO4?
      (c) Write the hybridisation and number of unpaired electrons in the complex [CoF6]3-. (Atomic No. of Co = 27)
  • Solution
    • (b)  Ionisation isomerism
      (c)
  • Question 20
    • Define the following with an example of each:
      (a) Polysaccharides
      (b) Denatured protein
      c) Essential amino acids
  • Solution
    • (a) Carbohydrates that give large number of                         monosaccharide units on hydrolysis which
      are units joined together by glycosidic linkage
      is called polysaccharides.
      e.g Starch , cellulose
      (b) These are the proteins that lose their biological               activity or in which secondary and tertiary                       structures are destroyed due to change in                         temperature or pH.
      e.g  The coagulation of egg on boiling.
  • Question 21
    • Write the structures of the main products in the following reactions:
  • Solution
  • Question 22
    • Give reasons:
      (a) E° value for Mn3+/Mn2+ couple is much more positive than that for Fe3+/Fe2+
      (b) Iron has higher enthalpy of atomization than that of copper.
      (c) Sc3+ is colourless in aqueous solution whereas Ti3+ is coloured
  • Solution
    • (a) Due to partial filled d-orbital of Mn2+ in                         Mn3+/Mn2+ and hence it has large +ve value to          reduce into Mn+2/Mn+3  In case of Fe3+/fe+2 ,            Fe3+ is already stable as it has half filled d orbital
      (b)Due to presence of higher unpaired electron in iron
      hence it has higher enthalpy of atomization
      (c) It is due to d-d transition shown by unpaired electron in d-orbital.In Sc+3 there are no d-electrons (it is colorless)
      Ti+3 there is one d-electrons.
  • Question 23
    • Shyam went to a grocery shop to purchase some food items. The shopkeeper packed all the items in polythene bags and gave them to Shyam. But Shyam refused to accept the polythene bags and asked the shopkeeper to pack the items in paper bags. He informed the shopkeeper about the heavy penalty imposed by the government for using polythene bags. The shopkeeper promised that he would use paper bags in future in
      place of polythene bags. [4] Answer the following:
      (a) Write the values (at least two) shown by Shyam.
      (b) Write one structural difference between low-density polythene and high density polythene.
      (c) Why did Shyam refuse to accept the items in polythene bags?
      (d) What is a biodegradable polymer? Give an example.
  • Solution
    • (a) * Careful for nature
      * Socially alert
      (b)

      Low Density Polythene High Density Polythene
      It is highly branched It is linear

      (c) Because polythene is non biodegradable
      (d) Those polymer which are degraded by                                   microorganisms are called biodegradable
      polymers
      E.g PHBV (Poly-β-hydroxybutyrate-co-β-                                                  hydroxyvalerate)

  • Question 24
    • (a) Write the reactions involved in the following:
      (i) Hofmann bromamide degradation reaction
      (ii) Diazotisation
      (iii) Gabriel phthalimide synthesis
      (b) Give reasons
      (i) (CH3)2NH is more basic than (CH2)3N in an                     aqueous solution.
      (ii) Aromatic diazonium Salts are more stable than                   aliphatic diazonium salts. OR  (a) Write the annums of the main products of the                     following reactions:
  • Solution
    • (a)
      (i)   (ii)  (iii) (b)
      (i)   ion is less hydrated than ‘s ion,                therefore tertiary amines have less tendency to                    form  o form ammonium ion and hence they are               least basic.
      (ii) Because of dispersed of positive charge over the                 benzene ring of Aromatic diazonium salts ,
      Hence they are stable as shown in fig but dispersion of charge is not present in aliphatic
      diazonium salts. OR
  • Question 25
    •  Give reasons:(a)
      (i) H3PO3 undergoes disproportionation reaction but H3PO4 does not.
      (ii) When Cl2 reacts with excess of F2. ClF3 is formed and not FCl3.
      (iii) Dioxygen is a gas while Sulphur is a solid at room              temperature.(b) Draw the structures of the following:
      (i) XeF4 (ii) HClO3 OR (a) When concentrated sulphuric acid was added to an unknown salt
      present in a test tube a brown gas (A) was evolved. This gas intensified
      when copper turnings were added to this test tube. On cooling, the gas
      (A) changed into a colourless solid (B). [5] (i) Identify (A) and (B).
      (ii) Write the structures of (A) and (B).
      (iii) Why does gas (A) change to solid on cooling?
      (b) Arrange the following in the decreasing order of their reducing
      character:
      HF, HCl, HBr, HI
      (c) Complete the following reaction:
      XeF4 + SbF5
  • Solution
    • (a)
      (i)
      H3PO3Oxidation No. of P is = +3
      H3PO4Oxidation No. of P is = +5
      In H3PO3, +3 oxidation state of phosphorus tends to disproportionate to higher (+5) and lower (–3) oxidation states in its respective compounds. On the other hand, in H3PO4 it is +5 which is the highest oxidation state. So it cannot undergo disproportionate reaction(ii)
      Since Fl can’t pack large size Cl atoms around it due to its
      * High electronegativity
      * Small Size
      *Absence of higher vacant orbitalTherefore FClis not formed
      (iii)
      Due to pπ-pπ bonding between O==O molecules of O2 so  weak vander waals present in it . Also it is small in size and have high electron density which tends to repel  O2 molecules. So it is gasSulphur does’nt have double bond hence it exist as Sheld together by strong covalent bonds and exists as a polyatomic molecule, in which intermolecular forces are strong so, it exists as a solid.(b) Or (i) A → NO2 (nitrogen dioxide)
      B → N2O4 (dinitrogen tetra oxide)
      (ii) Structure of A i.e NOand B i.e N2Oas underStructure of AStructure of B                    (iii)
    • NOis an odd electron species and hence it dimerizes to give N2Oon cooling
      (b) HI > HBr > HCl > HI(c)  XeF4 + SbF5 →[XeF3]+[SbF6]
  • Question 26
    • (a) Write the cell reaction and calculate the e.m.f. of the          following cell at
      298 K:
      Sn (a)| Sn2+ (0.004 M) || H+ (0.020 M) | H2(g) (1 bar) | Pt (s) (Given :
      E°Sn2+/Sn =- 0.14 V)
      (b) Give reasons:
      (i) On the basis of Eo values, O2+ gas should be                        liberated at anode but it
      is Cl2 gas which is liberated in the electrolysis of                 aqueous NaCl.
      (ii) Conductivity of CH3COOH decreases on dilution. Or (a) For the reaction
      2AgCl(s) + H2+(1 atm) → 2Ag(s) + 2H+
      (0.1 M) + 2Cl-
      (0.1M),
      ΔG° = – 43600 J at 25°C.
      Calculate the e.m.f. of the cell.
      [log 10-n = – n] (b) Define fuel cell and write its two advantages.
  • Solution
    • Cell reaction (a)  At Anode Sn → Sn+2+ 2e (ox) At Cathode 2H+ + 2e →H2 (aq)             (g)

      Sn + 2H+ →Sn+2+H2 (redox)
      EoCell = ESHE – ERHE

     =0.0 – (-0.14)
=0.14 V

(b) (i) Both Cl– and OH– ions are present near the anode. As the                    discharge potential of Cl– ions is  lower than that of OH-                      ions,  so Cl– ions are discharged in  presence to OH– ions.
(ii) On  dilution the degree of dissociation increases as a result                  molar conduction of acetic and increaes with dilution. OR    (a)
(i) (b)
Cells that convert the energy of combustion of fuels (like                       hydrogen, methane, methanol, etc.) directly into electrical                   energy are called fuel cells Advantage

  • Fuel cell works with an efficiency of 60 to 70 %
  • Pollution free source of energy.

Click Here To ViewLast Year Paper 2018

  • Question 1
    • A proton and an electron travelling along parallel paths enter a region of uniform magnetic field, acting
      perpendicular to their paths. Which of them will move in a circular path with higher frequency ?
  • Answer
    • Since electon has low mass so it moves faster in circular mass
  • Question 2
    • Name the electromagnetic radiations used for (a) water purification, and (b) eye surgery
  • Answer
    • (a) U.V
      (b) Laser
  • Question 3
    • Draw graphs showing variation of photoelectric current with applied voltage for two incident radiations of
      equal frequency and different intensities. Mark the graph for the radiation of higher intensity.
  • Answer
  • Question 4
    • Four nuclei of an element undergo fusion to form a heavier nucleus, with release of energy. Which of the two
      — the parent or the daughter nucleus — would have higher binding energy per nucleon?
  • Answer
    • Daughter nuclei has higher B.E  because it will be stable as compared to parent nuclei
  • Question 5
    • Which mode of propagation is used by short wave broadcast services
  • Answer
    • Sky waves
  • Question 6
    • Two electric bulbs P and Q have their resistances in the ratio of 1 : 2. They are connected in series across a
      battery. Find the ratio of the power dissipation in these bulbs.
  • Answer
    • \dpi{100} \frac{R(P)}{R(Q)}=\frac{1}{2} In series we know that I(P) = I(Q) \dpi{100} \frac{Power dissipation (P)}{Power dissipation (Q)}=\frac{I^{2}(P)R(P)}{I^{2}(Q)R(Q)}\dpi{100} =\frac{1}{2}
  • Question 7
    • A 10 V cell of negligible internal resistance is connected in parallel across a battery of emf 200 V and internal
      resistance 38Ω as shown in the figure. Find the value of current in the circuit. OR
    • n a potentiometer arrangement for determining the emf of a cell, the balance point of the cell in open circuitis 350 cm. When a resistance of 9 Ω is used in the external circuit of the cell, the balance point shifts to 300cm. Determine the internal resistance of the cell.
  • Answer
    • Since
      E=200 – 10
      =190 \dpi{100} I=\frac{V}{R}=\frac{190}{30}=20 A   OR
    • We have given that
      Potentiometer at open circuit l1=350 cm
      R=9Ω l2=300 cm
      Internal Resistance r =\dpi{100} 9(\frac{350}{300}-1)Ω =1.5 Ω
  • Question 8
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Class X Solved Paper

Sicence Previous Solved Paper

Chemestry

Chemical reactions & equations

1. Chemical reactions & equations

Q.1 a) Why is respiration considered an exothermic reaction?
b) Identify the substance that is oxidized and reduced in the reaction:
CuO (s) + Zn (s) → Cu (s) + ZnO (s).
c) Identify the oxidizing agent and reducing agent in the reaction:
3Fe + 4H 2 O → Fe 3 O 4 + 4H 2

1

1/2+1/2

1/2+1/2

Ans
  1. because heat is evolved during reaction
    • Oxidised — Zn
    • Reduced — CuO
    • Oxidizing agent — H 2 O
    • Reducing agent– Zn

1

1/2+1/2

1/2+1/2

 

Q.2
  1. What change in colour is observed when white silver chloride is left exposed
    to sunlight? State the type of chemical reaction in  this change.
  2. Why do potato chips manufacturers fill the packet of chips with nitrogen
    gas?
  3. Why do gold and platinum not corrode in moist air?

1

1

1

Ans
  1. becomes grey.
    photo-chemical decomposition reaction
  2. To protect it from becoming rancid.
  3. Are least reactive.

1/2
1/2

1

1

 

Q.3 What happens when quick lime is dissolved in water? Write the balanced chemical equation. Write the type of reaction that has occurred. 3
Ans Slaked lime is formed with the evolution of heat.
CaO (s) + H2O → Ca(OH)2 + Heat
Combination as well as exothermic reaction.
1+1+1
Q.4

Write balanced equation for the following:

  1. Magnesium (s) + Hydrochloric acid (aq) → Magnesium chloride (aq) + Hydrogen (g)
  2. Zinc carbonate (s) → Zinc oxide (s) + Carbon dioxide (g)
  3. Silver chloride (s) → Silver (s) + Chlorine (g)
3
Ans
  1. Mg (s) + 2HCl (aq) → Mg(Cl)2 + H2
  2. Zn(CO)3(s) → ZnO(s) + CO2(g)
  3. 2AgCl(s) → 2Ag(s) + Cl2
1+1+1
Q.5 Give one example of decomposition reaction which is carried in the presence
of:

  1. electrical energy,
  2. sunlight,
  3. heat energy.
3
Ans
  1. Electrolysis of water
  2. Decomposition of silver chloride,
  3. Decomposition of lead nitrat
1+1+1
Q.6
  1. An iron knife kept dipped in a blue copper sulphate solution turns the blue
    solution light green. Why?
  2. During electrolysis of water, gas collected in one test tube is double than
    other. why?
3
Ans
  1. As we know iron is more reactive than copper. So, it displaces Cu from CuSO4
    solution and forms ferrous sulphate which is of Light Green Colour.
    CuSO4 (aq) + Fe (s) → FeSO4 (aq) + Cu(s)
    Blue colour                     light green colour
  2. On electrolysis weter decompose into hydrogen and oxygen in ratio 2:1 by
    volume so,H2 gas collected in one test tube is double than O2.
2+1

Acids, Bases & Salts

2. Acids, Bases & Salts

Q.1

For making cake, baking powder is taken. If at home, your mother uses baking
soda instead of baking powder in cake,

  1. how will it affect the taste of the cake and why?
  2. how can baking soda be converted into baking powder?
  3. what is the role of tartaric acid added to baking soda?

1

1

1

Ans
  1. If only baking soda is used, sodium carbonate formed will not be
    neutralized and the cake will taste bitter.
  2. Baking soda can be converted into baking powder by mixing it with an
    appropriate amount of tartaric acid.
  3. Tartaric acid neutralizes the sodium carbonate formed on heating
    NaHCO3 so the cake will not taste bitter.
1+1+1
Q.2

Write balanced equations to represent the reaction of hydrochloric acid with

  1. Zinc metal,
  2. metal carbonate,
  3. metal hydrogen carbonate.
3
Ans
  1. Zn (s) + 2HCl (dil) → ZnCl2 (aq) + H2 (g)
  2. K2 CO3 (s) + 2HCl (dil) → 2KCl (aq) + H2O (l) + CO2 (g)

    (With any other metal carbonate)

  3. KHCO3 (s) + HCl (aq) → KCl (aq) + H2O (l) + CO2 (g)
    (With any other metal hydrogen carbonate
    )

1

1

1

Q.3

A milkman adds a very small amount of baking soda to fresh milk.

  1. Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
  2. Why does this milk take a long time to set as curd?
3
Ans
  1. He makes milk slightly alkaline so that it may not get sour easily.
  2. Lactic acid formed has to neutralize the alkali present in it. Explanation.
3
Q.4

Write down the chemical name and formulae for the following
compounds:

  1. Bleaching powder
  2. Washing soda
  3. Plaster of paris.
3
Ans
  1. Calcium oxychloride CaOCl2
  2. Sodium Carbonate decahydrate Na2CO3 .10H2O
  3. Calcium Sulphate hemihydrate CaSO4.1/2H2 O.

1

1

1

Q.5 What is a neutralization reaction? Give two examples. 1
Ans

A reaction in which an acid and a base react to give a salt and water is known as a
‘neutralization reaction’. For example,

  • NaOH (aq) + HCl (aq) –> NaCl (aq) + H2O (liq)
  • Ca(OH)2 (aq) + H2SO4(aq) –> CaSO4 (s) + H2O(l)
1+1+1
Q.6
  1. What is a universal indicator? What is its advantage?
  2. Name a strong base and a weak base.
3
Ans
  1. A universal indicator is a mixed indicator of organic chemicals which not only
    shows whether the given solution is acidic or basic, but also shows the approximate
    pH values by giving a wide particular colour for a specific value of pH.
  2. A strong base is sodium hydroxide (NaOH) and a weak base is ammonium
    hydroxide (NH4OH).
2+1

Metals & Non-metals

3. Metals & Non-metals

Q.1

Explain how the following metals are obtained from their compounds by the
reduction process:

  1. Metal X which is low in the reactivity series.
  2. Metal Y which is in the middle of the reactivity series.
  3. Metal Z which is high up in the reactivity series.
3
Ans
  1. Metal X (very less reactive)- its oxide is reduced by the action of heat alone.
  2. Metal Y (moderately reactive)- its oxide is reduced by chemical reduction i.e. with reducing agents like carbon, sodium, aluminium.
  3. Metal Z (highly reactive)- its compounds are reduced to metal by electrolytic reduction.

1

1

1

Q.2

Give reasons for the following :-

  1. Metals are good conductors of electricity whereas non-metals are not.
  2. Ionic compounds have usually high melting and boiling points.
  3. Ionic compounds conduct electricity in molten state.
3
Ans
  1. Metals have free electrons to move
    Non-metals have no free electrons to move
  2. Considerable amount of energy is required to break the strong inter- ionic
    attraction.
  3. The electrostatic forces of attraction between the oppositely charged ions
    are overcome by the heat and ions become free to move.

1/2
1/2

1

1

Q.3
  1. Write the electronic configuration of Sodium and Chlorine.
  2. Show the formation of sodium chloride from sodium and chlorine by the
    transfer of electrons. Name the cation and anion present in the ionic
    compound formed.
3
Ans
    • Na – 2 8 1
    • Cl – 2 8 7
  1. Cation — Na+ / Sodium
    Cation — Cl / Chloride

1/2
1/2

1

1/2
1/2

Q.4
  1. What do you mean by amphoteric oxide?
  2. Give an example of a metal which
    1. Is a liquid at room temperature.
    2. Is kept immersed in kerosene for storing.
    3. Is both malleable and ductile.
    4. Is the best conductor of heat.
3
Ans
  1. Substance which behaves both as an acid and as a base.
  2. Give an example of a metal which
    1. Mercury/ Hg
    2. Na / K
    3. Cu/ Zn/ Al/ Ag ( or any other)
    4. Ag/ Cu

1

1/2
1/2
1/2
1/2

Q.5 Describe ‘electrolytic refining’ of impure copper with the help of labelled
diagram to illustrate it.
3
Ans

  • Electrolytic Refining: Many metals, such as copper, zinc,tin, nickel, silver, gold, etc., are refined electrolytically. Inthis process, the impure metal is made the anode and athin strip of pure metal is made the cathode. A solution ofthe metal salt is used as an electrolyte. The apparatus isset up as shown in Fig. . On passing the currentthrough the electrolyte, the pure metal from the anodedissolves into the electrolyte. An equivalent amount of pure metal from the electrolyte is deposited on the cathode. The solubleimpurities go into the solution, whereas, the insoluble impurities settledown at the bottom of the anode and are known as anode mud.
 
Q.6 What is corrosion? Write any four methods of preventing corrosion? 3
Ans

Corrosion is a natural process, in which corroded after some period of time due to chemical changes like its oxide , hydroxide or sulfile

Methods of preventing corrosion

  • Paint should apply to metal to avoid corrosion
  • Anodizing makes a material more resistant to weathering and corrosion and is commonly used on metal applications where the surface will be in constant contact with the elements.
  • Galvanization metal is coated with a thin layer of zinc to protect it against corrosion. The zinc oxidizes when it is exposed to air creating a protective coating on the metal surface.
  • By cathodic protection by applying an opposing electrical current to the metal ‘s surface

1

1/2
1/2
1/2
1/2

Q.7 What is Thermite reaction? Differentiate between calcination and roasting. 3
Ans

Fe2O3 + 2Al →2Fe + Al2O3 + Heat

Calcination – Heating the carbonate ore in limited supply of air.
Roasting _ Heating the sulphide ore in excess air.

1+2

Carbon & its compounds

Carbon & its compounds

Q.1
  1. What are detergents?
  2. Write merits & demerits of using detergents for cleaning.
3
Ans
  1. Detergents are ammonium or sulphonate salts of long chain carboxylic acids.
  2. Merit – Could be used in hard water/more and rapid cleansing action
    Demerit – Acts as pollutant / non biodegradable.
1+2
Q.2 Explain the mechanism of the cleansing action of soap. 3
Ans

Since soap molecules contains long chain of hydrocarbon (non ionic hydrocarbon tail ) and small ionic end as shown below

C17H35COONa        →      C17H35                  +               COO Na +
Sodium Stearate                   Long Hydrocarbon                Ionic end
                                            chain
                                                       ↓                                     ↓   
                                             Hydrophobic                         Hydrophilic
                                           (Water repelling)                     (Water Attracting)

When detergent or soap molecule is added to water it form layer of non polar hydrocarbon chain . When dirty clothes is
dissolved into water than soap molecule in water align themselves in radial cluster around the dust present in clothes
which is also known micelles .

The hydrocarbon end of soap molecules are directed toward center and while ionic end directed away from the center .
The dust molecule is organic in nature which attracted toward hydrocarbon tails . This process occurs continously
until whole dirt attract toward the hydrocarbon chain and finally it dispatch from the clothes .   

 
Q.3
  1. Draw the electron-dot structure of ethene.
  2. Which of the following compounds can have a double bond?
    C4H10, C5H8 , C5H10
  3. Name the following compounds
    1. CH3-CH2-CH2-CHO
    2. CH3-CH2-Br
3
Ans
  1. Ethene Structure
  2. C5H10
  3. Name the following compounds
    1. Butanol
    2. Bromoethane
1+1
+1/2+
1/2
Q.4
  1. Identify the functional group in the following compounds
    1. Ethanoic acid
    2. Butanone
    3. Ethanol
    4. Propanal
  2. Give an example of addition reaction in unsaturated hydrocarbon.
3
Ans
    1. Carboxylic acid -COOH
    2. Ketnone -CO-
    3. Alcohol-OH
    4. Aldhyhide-CHO
  1. When unsaturated hydrocarbon add hydrogen in the presence of catalysts
    such as palladium or nickel to give saturated hydrocarbons.
    e.g Vegetable oils
2+1
Q.5
  1. Why does carbon forms large number of compounds?
  2. Name any two allotropes of carbon.
  3. How many covalent bonds are there in a molecule of ethane, C2H6 ?
3
Ans
  1. Due to its tetracovalent nature and catenation property
  2. Diamond and Graphite
  3. 7
1+1+1
Q.6 What are esters? Name an ester formed when ethanoic acid reacts with
ethanol. Write a balanced chemical equation for it.
3
 

An organic compound made by replacing the hydrogen of an acid by an alkyl or
other organic group are called esters

Ethanoic acid reacts with ethanol in the presence of concentrated sulphuric acid as a catalyst to produce the ester, ethyl ethanoate. The reaction is slow and reversible. To reduce the chances of the reverse reaction happening, the ester is distilled off as soon as it is formed

CH3COOH  +   CH3CH2OH     ⇔  CH3COOCH2CH3   +  H2O
Ethanoic acid        Ethanol                   esters or ethyl ethanote  Water

 
Periodic classification of elements

Periodic classification of elements

1

How would the following properties of the element vary along the period from
left to right in the modern periodic table? Give reasons.

  1. Tendency to lose electrons
  2. Atomic size
  3. Valency.
3
Ans
  1. Decreases – as the effective nuclear charge acting on the valence shell                     electrons increases across the period from left to right,                     the tendency to lose electrons will decrease.
  2. Decreases – as electrons are added in the same shell & effective                     nuclear pull increases due to the increase in the number of                     protons in the nucleus, leading to decrease in the size of                     the atom from left to right.
  3. Valency of elements increases from 1 to 4 & decreases to zero as we move from
    left to right along the period.
1+1+1
2
  1. Name the scientist who proposed the Modern Periodic Law of classification
    of elements.
  2. State Modern Periodic Law of classification of elements.
  3. What are the demerits of Mendeleev’s Periodic Table?
3
Ans
  1. Henry Moseley
  2. Elements are arranged according to the periodic function of their atomic numbers
  3. Demerits of Mendeleev’s Periodic Table is as under
    • Postion of hydrogen is not explained
    • Isotopes postion is not clear
    • Elements having higher atomic mass preceeds the elements having lower atomic masses
3
3
  1. Find the atomic number of the element whose electronic configuration is 2, 8,
    5.
  2. Account for the following:
    1. Elements in a group of the periodic table have similar chemical properties.
    2. Elements of group 18 are called zerovalent.
3
Ans
  1. Atomic number = 2 + 8 + 5 = 15
    1. The chemical properties of an element are determined by its valance
      electrons. Since in a group all the elements have the same number of valence
      electrons, they exhibit similar chemical properties.
    2. Group 18 elements have their outermost shell complete.
3
4

How the following properties of elements vary in a periodic table when we
move from top to bottom in a group:

  1. Atomic size,
  2. Metallic property,
  3. Valency .
    Justify your answer.
3
Ans

 

  1. Atomic size, Increase because number of outermost shell increases
  2. Increase because number of charged electron increases
  3. Remain same because number of outer most electron on moving top to bottom are same
1+1+1
5 Differentiate between the arrangement of elements in Mendeleev’s periodic
table and Modern periodic table.
3
Ans
S.No Mendeleev’s Periodic table Modern periodic table
1 The elements are arranged according to increased atomic masses The elements are arranged according to increased atomic number
2 Postion of hydrogen is unjustified because it resembles both with alkali metals and halogens Postion of hydrogen is mention and it resembles with alkali metal due to similar chemical and physical properties
3 Position of isotopes was not justified The was no problem in the placing of isotopes
3

Biology

Life Process

Life Processes

1
  1. Name one gland in human body which secretes digestive enzymes as well as
    hormones.
  2. Give reasons for the following:-
    1. The lung alveoli are covered with blood capillaries.
    2. The wall of trachea is supported by cartilage rings.
3
Ans
  1. Pancreas
    1. Because walls of alveoli diffuses with the air inhaled in it which
      helps the exchange of gases.
    2. To prevent it from collapsing when there is no air.
3
2

Draw the diagram of human respiratory system and label on it:

  1. larynx,
  2. trachea,
  3. lungs,
  4. bronchi.
3
Ans Respiratory System  
3

Give reasons for the following:-

  1. The muscular wall of ventricle are thicker than the walls of aorta.
  2. Arteries have thick elastic walls.
  3. The colour of Human blood is red
3
Ans
  1. Ventricles have to pump blood into various organs.
  2. They receive and carry the blood with high pressure.
  3. Due to high number of RBCs(Hb)
1+1+1
4 Draw the flow chart to show the three ways in which glucose is broken down. 3
Ans Breakdown of glucose in three pathways 3
5 List the steps of Photosynthesis. Write down the chemical equation involved 3
Ans

The following steps occurs in the process of photosynthesis

  1. Absorption of light energy by chlorophyll.
  2. Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
  3. Reduction of carbon dioxide to carbohydrates.

 

                                       Chlorophyll
6CO2      +       12H2O           →            C6H12O6      +      6O6       +    6H2O
                                           Sunlight         (Glucose)

3
6 Write down the functions of HCl, mucus and pepsin secreted by the glands of
the stomach wall
3
Ans HCl- Creates an acidic medium and activates the protein digesting enzyme, Kill
          germs.
Mucus- Protects the inner lining of the stomach wall from HCl
Pepsin- It digests the protein.
1+1+1
Control & Coordination

Control & Coordination

1

Which animal or plant hormone is associated with the following?

  1. Changes at puberty in males.
  2. Changes at puberty in females.
  3. Inhibits growth of plants.
  4. Promotes cell division in plants.
  5. Dwarfism.
  6. Goitre.
3
Ans
  1. Testosterone hormone
  2. Estrogen hormone
  3. Abscisic acid (ABA)
  4. Cytokinins hormone
  5. Growth hormone (GH).
  6. Thyroxin hormone..
1/2 X 6=3
2
  1. What is geotropism? Draw a diagram to show positive phototropic and
    negative phototropic movement in plant.
3
Ans
  1. It is the movement of parts of the plant in response to gravity.

positive phototropic and

3
3
  1. Name the three major regions (parts) of the human brain. Which part of the
    brain maintains posture and equilibrium of the body?
  2. How are our brain and spinal cord protected?
3
Ans
  1. The three major regions (parts) of the human brain.
    1. Fore-brain,
    2. Midbrain,
    3. Hind-brain

      Cerebellum( Hind-brain) maintains posture and equilibrium of the body

  2. Brain –inside bony cage called cranium or skull.
    Spinal cord—vertebral column.
1/2 x 6 = 3
4

Identify the glands and mention hormones produced .

  1. Gland which prepares our body to function at maximum efficiency during
    anger or danger.
  2. Gland that helps in growth of bones and muscles.
  3. Gland that helps in growth of secondary sexual characters in males.
3
Ans
  1. Adrenal gland, hormone is adrenaline.
  2. Pituitary gland, hormone is growth hormone
  3. Testes,testosterone.
6 x 1/2
5 What is Reflex Action? Draw a flowchart diagram of reflex arc. 3
Ans It is a rapid automatic, unconscious and involuntary response of the body to a
stimulus without involving the brain.
Reflex Arc
1+2
6
  1. What is synapse?
  2. Name the hormone that helps in regulating level of sugar in our blood. Name
    the gland that secretes it.
3
Ans
  1. The functional junction between neurons for the transfer of information i.e. nerve
    impulse from one neuron to the next.
  2. Hormone : Insulin
    Gland : Pancreas
3

How do organisms Reproduce?

How do organisms Reproduce?

1 What does HIV-AIDS stand for? Is it a STD? Name three more STDs. 3
Ans

HIV-Human Immuno Deficiency Virus
AIDS-Acquired Immuno Deficiency
Syndrome

Yes they are STD ( Sexually transmitted diseases )

Three more STDs are as under

  1. Gonorrhoea,
  2. Syphilis,
  3. Genital Herpes
3
2 What is binary fission? With the help of suitable diagrams, describe this in Amoeba. 3
Ans Its an asexual reproduction where a single mature cell splits into two daughter cells
Binary Fission in Amoeba
Clearly from the fig When Amoeba cells reaches its maximum size than Amoeba reproduces
by binary fission and divides its body into two parts .In this way each parts of amoeba when
reaches to its maximum size than they too divedes into parts
3
3
  1. Name the female & the male reproductive glands which produces gametes.
  2. State the hormones produce by the above glands.
  3. Where does fertilization occur in case of human female & name the place
    where fertilized egg gets implanted?
3
Ans
  1. Female Reproductive Glands – Ovary
    Male Reproductive Gland – Testes
  2. Ovary– Progesterone & estrogen
    Testes– testosterone
  3. Oviduct/fallopian tube on the lining of the uterus
3
4
  1. Name two glands that contribute fluid to the semen.
  2. State two advantages semen offers to the sperms.
  3. Why are testes in males located outside the abdominal cavity in scrotum?
3
Ans
  1. Two glands that contribute fluid to the semen.
    ( Choose any two)

    1. Prostate glands
    2. Seminal vesicles
    3. Cowper’s glands
  2. Two advantages semen offers to the sperms.
    1. Semen provides nutrition for the sperms.
    2. Semen makes the transport easier for the sperms through its fluid medium.
  3. Sperm formation requires a low temperature than the normal body temperature
    (2-3 o C less)
1+1+1
5 Draw a labelled diagram of the longitudinal section of a flower/ male reproductive system/ female reproductive system 3
Ans


The reproductive parts of angiosperms are located in flower .There are different parts of flower as under

  1. Sepals
  2. Petals
  3. Stamens
  4. Carpels

Stamens are carpels are the male reproductive parts of flower which contains the germcells and produce pollen
grains and yellowish colour
and carpel is female reproductive part which is present
in center present in the center
of flower . Carpel has three parts

  1. Carpel

    1. Stigma →Terminal part of flower
    2. Style →Middle elongated part is the style
    3. Ovary →Swollen bottom part is the ovary.
3
6
  1. What are the advantages of sexual reproduction over asexual reproduction?
  2. What is the importance of DNA copying in reproduction?
3
Ans
  1. Sexual reproduction leads to variation due to recombination of genetic material
    DNA. These variations are essential for survival of species. On the contrary, asexual
    reproduction does not bring variations.
  2. DNA contains information for inheritance of features from parents to next
    generation. DNA present in the cell nucleus is the information source for making
    proteins. If the information is different, different proteins will be made. Different
    proteins will eventually lead to altered body designs.
 
Heredity & Evolution

Heredity & Evolution

1
  1. Name the animal in which eyes developed for the first time.
  2. Identify analogous and homologous organs amongst the following:
    Wings of an insect, wings of a bat, forelimbs of a frog, forelimbs of a human.
3
Ans
  1. Planaria
  2. Analogous organs: Wings of insect, wings of a bat.
    Homologous organs: Forelimbs of a frog, forelimbs of a human.
3
2 Study the given data and answer the questions following the data:

Parental plants cross
fertilized and seeds
collected
F1 (first generation
offsprings)
F2(offsprings of self
pollination of F1)
Male parent always bore
red flowers.
Female parent always
had white flowers
330 seeds sown and
observed.
All 330 gave red
flowers.
Out of 44 seeds 33
seeds gave plants
with red flowers &
11 seeds gave plants
with white flowers.
  1. What is the term used for this type of cross?
  2. What does the data of the column marked F1 indicate?
  3. Express the genotype of the F1 and F2 progeny.
3
Ans
  1. Monohybrid cross.
  2. Red colour of flower is dominant over white colour of flower.
  3. F1 progeny- Rr
    F2progeny- RR, Rr, rr.
3
3
  1. What is speciation?
  2. What are the factors responsible for speciation?
  3. Name two plants which are developed from wild cabbage.
3
Ans
  1. Origin of new species from the existing ones
  2. The factors responsible for speciation are as under
    • Physical barrier,
    • Genetic drift,
    • Reproductive isolation,
    • Variation
  3. Two plants which are developed from wild cabbage. (Any two)
    • Cabbage,
    • Cauliflower,
    • Kale
    • Broccoli,
3
4 What is the scientific name of human? Why are human beings who look so different
from each other in terms of size, colour & looks said to belong to the same species? Name
the method which is extensively used to define evolutionary relationships.
3
Ans

Scientific name of human is Homo Sapiens

Because they can interbreed to produce fertile offsprings i.e.
sons & daughters

Molecular Phylogeny ( i.e comparative study of DNA of different species)

3
5 Differentiate between acquired and inherited traits? 3
Ans
Acquired traits Inherited traits
Character developed in the organisms during their life time Characters received from parents
Do not bring any change in the genes Bring about changes in genes
Lost with the death of the individual Transmitted to the next generation
3
6 Why fossils are considered important in the study of evolution? Explain two ways by
which age of fossils can be estimated.
3
Ans

Fossils provide evidence in favour of evolution / establish evolutionary
relationships by providing missing links.

Ways by which age of fossils can estimated

  1. Relative method – Fossils found closer to the surface are more recent
                                    than those in deeper layer.
  2. By detecting the ratios of different isotopes of the same element in the
    fossils material.
3
Our Environment

Our Environment

1
  1. Why do food chains in an ecosystem do not have more than 4 to 5 trophic levels?
  2. How much energy flows from one trophic level to next in a food chain?
 
Ans
  1. The loss of energy at each trophic level is great.

    Very little usable energy remains after 4 or 5 trophic levels.

  2. 10%
 
2
  1. Identify which one of the following would have a hazardous impact if they persist in the environment for a long time.
    Newspaper, vegetable peels, pesticides, waste from cattle shed.
  2. Phytoplanktons → Zooplanktons → Fish → Fish eating birds.
    In the above food chain, which organisms will have

    1. maximum available energy?
    2. maximum concentration of pesticides? Name the phenomenon associated with it Define the phenomenon.
 
Ans
  1. Pesticides
    1. Phyto-planktons will avail maximum energy.
    2. Fish eating birds will have maximum concentration of pesticides.
      Biomagnification
 
3 ‘‘Energy flow in food chains is always unidirectional.’’ Justify this statement. What is a
food web?
 
Ans
  • In a food chain the energy moves progressively through the various trophic levels and is no
    longer available to the organisms of the previous trophic level / energy captured by the
    autotrophs does not revert back to the solar input.
  • A food web consists of a series of branching networks of various food chain interconnected
    at various trophic levels
 
4
  1. What will be the amount of energy available to the organisms of the 2nd trophic level
    of a food chain, if the energy available at the first trophic level is 10,000 joules ?
  2. Classify the following ecosystems into natural and artificial ecosystem.
    Forest ecosystem, aquarium, marine ecosystem, cropland ecosystem
 
Ans
  1. 10 % of 10,000 = 1000
  2. Natural ecosystem: Forest ecosystem, marine ecosystem
    Artificial ecosystem: aquarium, cropland ecosystem
 
5 What is ozone ? How and where is it formed in the atmosphere ? Explain how does it
affect an ecosystem.
 
Ans Ozone (O3) is a molecule formed by three atoms of oxygen.
Ozone is formed at the higher levels of the atmosphere by action of UV radiation on oxygen
(O2 ) molecule.
The higher energy UV radiations split apart some moleculer oxygen (O2 ) into free oxygen(O)
atoms. These atoms then combine with the molecular oxygen to form ozone as shown—

O2 (UV)→ O + O
then, O + O2 → O 3 (Ozone)

Ozone shields the surface of the earth from ultraviolet (UV) radiation from the Sun. This
radiation is highly damaging to organisms, for example, it is known to cause skin cancer
in human beings.

 
6 What is an ecosystem? Lists its two main components. Why do we not clean ponds or lakes but an aquarium needs to be cleaned regularly  
Ans

An ecosystem is made of all the plants, animals and microorganisms in an area along with non-living
components such as climate, soil, river deltas etc.

Components of ecosystem

  1. Biotic
  2. Abiotic

Ponds or lakes have natural cleaning agents like decomposers but an aquarium lacks such cleaning agents.

 
Management of Natural Resources

Management of Natural Resources

1
  1. What do you mean by ‘water harvesting’? Mention two traditional methods of water
    harvesting of our country.
  2. Identify two local industries which pollute the local water bodies by throwing
    untreated sewage.
 
Ans
  1. Storage of rain water & runoff water to recharge the ground water

    Traditional methods of water harvesting of our country

    1. Jhalaras ( Tank to collect rainwater specially in Rajasthan and Gujarat. ) The walls of jhalaras are sorrounded by left and right stairs for collecting rainwater
    2. Tank shape terrace for collecting rainwater
  2. Local industries which pollute the local water bodies by throwing
    untreated sewage. (Any two)

    1. Paper industry
    2. Sugar industry
    3. Paint and varnish industry
    4. Chemical and fertilizer
 
2 List three advantages associated with water harvesting at the community level.  
Ans

Three advantages associated with water harvesting at the community level are

  1. Recharges ground water
  2. Mitigates floods and droughts
  3. Brings rivers and wells back to life and makes more water available
 
3 Every one of us can do something to reduce our personal consumption of various natural
resources. List three such activity based on 3 – R approach.
 
Ans

Three activities every one of us can do to reduce our personal consumption of various natural
resources:

  1. Reduce excessive use of natural resources like water, fossil fuels, etc..
  2. Reuse of some resources instead of wasting (throwing) them, like empty bottles.
  3. Recycle the materials like paper to reduce the pressure on existing natural resources.
 
4 Who are stakeholders? List four stakeholders which may be helpful in the conservation
of forest.
 
Ans

A stakeholder can be a person, a group or an organisation that may be affected or have any
kind of interest or in the project or in the project outcome either directly/indirectly.

  1. Local people
  2. Industrialist
  3. Wild life and nature enthusiasts
  4. Forest department
 
5 Building of big dams gives rise to some problems. List three main problems that may
arise. Suggest a solution to any one of these problems.
 
Ans

Three main problems that may arise while building dams

  1. Local people
  2. Industrialist
  3. Wild life and nature enthusiasts
  4. Forest department

Solution is Adequate rehabilitation / compensation to the displaced persons / aforestation

 

Physics

Light- Reflection & Refraction

Light- Reflection & Refraction

1

An object of size 7 cm is placed perpendicular to the principal axis at a distance of 27 cm
in front of a concave mirror. The focal length of the mirror is 18 cm. Find the

  1. position
  2. size and
  3. nature of the image produced.
 
Ans

Given

h = 7cm
u = -27cm
f = -18cm
v = ?
h1 = ?


  1.              v = -54 cm
  2. Magnification
  3. Image is real , inverted & two times enlarged

 

 
3
  1. Define 1 dioptre of power of a lens.
  2. Two lenses have power of i) +2D & ii) -4D. Find out the focal length & nature of
    each lens.
 
Ans
  1. One dioptre is the power of a lens whose focal length is 1 m.
    1. P = +2D
      P=1f

      f=1P

      f=12 = 0.5 m = 50 cm

      Since power is +ve , so lens is convex lens

    2. P = +4D
      P=1f

      f=1P

      f=14 = 0.25 m = 25 cm

      Since power is -ve , so lens is concave lens

 
3 What is lateral displacement? State two factors on which it depends?  
Ans

The shifting in the emergent ray with respect to the incident ray on passing light ray from
glass slab is called lateral shift or lateral displacement. Lateral displacement depends mainly on:

  1. Angle of incidence
  2. Thickness of glass slab
  3. Refractive index of glass slab.
 
4 Write three applications each of concave and convex lens  
Ans

Three uses of concave lens:

  1. In spectacles for eyes suffering from myopia.
  2. In the lens combination of camera, telescope.
  3. In door hole lenses.

Three uses of convex lens:

  1. In spectacles for eyes suffering from hypermetropia.
  2. In the lens combination of camera, telescope, microscope
  3. It is also used as a magnifying lens
 
5
  1. The radius of curvature of a spherical mirror is 20 cm. What is its focal length?
  2. Why do we prefer a convex mirror as a rear-view mirror in vehicles?
 
Ans
  1. Focal length

    f=R2

    f = 202 = 10 cm

  2. We prefer a convex mirror as a rear-view mirror in vehicles because it gives a wider field of view, which allows the driver to see most of the traffic behind him. Convex mirrors always
    form a virtual, erect, and diminished image of the objects placed in front of it.
 
6 Draw ray diagrams to show the formation of an image formed by a concave mirror and
a convex lens when an object is placed between focus and pole of the mirror and focus
and optical centre of the lens.
 
Ans

Formation of an image formed by a concave mirror

Formation of an image formed by a Convex lens

 
Human Eye & Colourful World
Electricity
Magnetic Effects of Electric Current
Sources of energy

Social Science Previous Most Important Solved Questions

History-India and the Contemporary World – II

The Rise of Nationalism in Europe

Class X

History

(India and the Contemporary World – II)

The Rise Of Nationalism in Europe

Short Type Questions ( 3 Marks )

Q.1 Explain the greek war of independence ?

Ans

  • Greek under Ottoman Empire
  • Growth of Nationalism sparked the struggle.
  • Got support from Western Europeans
  • Poets and artists lauded Greece
  • Finally with Treaty of Constantinople Greece became independent.

Q.2 Why 1830’s is called the year of Economic hardship ?

Ans

  • Population of Europe increase
  • Unemployment spread among people
  • Rat race competition began for small producer
  • Poverty rise due in increase the rate of food prices

Q.3 What were the measures taken by French revolutionaries to forge a sense of collective identity?

Ans

  • Through the ideas of “la patrie and le citiyon
  • New tricolor flag
  • Composition of new system of hymns and commemoration of martyrs
  • Formulating uniform laws for all citizens.

Q.4 Explain the consequences of the Vienna congress

Ans

  • The Bourbon dynasty was restored in France,
  • A number of states were set up on the boundaries of France.
  • Prussia was given important new territories,
  • Austria got control of northern Italy,
  • Russia was given part of Poland.

Q.5 How was the history of nationalism in Britain unlike the rest of Europe?

Ans

  • In Britain, the ethnic groups consisting of the English, Welsh, Scot
    and Irish had their own culture and political tradition.
  • The English parliament had seized power from the monarchy in 1688.
    The act of union made Scotland to come under England. Ireland was
    forcibly incorporated into the United Kingdom in 1801.
  • The symbols of New Britain, the British flag, the national anthem the
    English language were actively promoted.

Q.6 What is the other name for Napoleonic code? Write any four changes brought by this.

Ans The Napoleonic code also known as civil codes of 1804. Changes in france brought
       by this codes is as
under

  • Did away privileges based on birth
  • Established equality.
  • Secured right to property.
  • Simplified administrative division and abolished feudal system.

Q.7 How did France benefit from the revolution?

Ans The revolution benefit france in the following way

  • New administrative system in France was formed
  • Constitution assembly was formed to run the government
  • A new flag was introduced to spread patriotism among people.
  • New songs were composed

Long Type Questions ( 5 Marks )

Q.1 What were the ideals of liberal Nationalism?

Ans The ideas of liberal Nationalism is as under

  • Freedom for individual
  • Equality of all before law
  • Concept of Govt. by consent.
  • End of autocracy
  • Freedom of market

Q.3 Explain the different stages of unification of Germany.

Ans

  • Germany was group of small states before its unification.
  • The liberal initiative to Nation building failed and was taken over by
    Prussian empire. Otto von Bismarck was the chief architect in German Unification.
  • He led three wars against Austria, Denmark and France which ended in Prussian
    victory. In 1871 Prussian King William I, was declared German Emperor.

Q.4 Briefly explain the unification of Italy, highlight the value you learn from this.

Ans

  • During the middle of 18th century, Italy was divided into seven states of which
    Sardinia and Piedmont were under princely states.
  • North, under Austria,Centre ruled by Pope and South ruled by Spain.
  • The main leaders were Victor Immanuel II of Sardinia, Chief Minister Count Cavour Mazzini
    and Garibaldi. With their initiative in 1861 Victor Emmanuel
    was declared king of united Italy.
  • Value highlighted in this is love, unity, National

Q.5 Briefly explain Balkan Issue.

Ans

  • Balkan was region of Geographical and ethnic variation comprising of Romania Bulgaria,
    Albania Greece, and Macedonia, Croatia ‘Bosnia-Herzegovina, Slovenia, Serbia and
    Montenegro who were all together called slaves.
  • Till the last part of 19th century, this was under Ottoman Empire. The disintegration of the
    Ottoman Empire and emergence of Romantic Nationalism made this region a land of conflict.
  • Balkan nations tried to capture more territories from neighboring places. It also became a
    scene of big power rivalry like Russia, Germany, England and Austria, Hungary.
    Ultimately it led to open wars and finally led it to the First World War.

Q.6 Why was Frankfurt National assembly convened? Why did it fail?

Ans

  • It was convened in 1848 to vote for anall-German National Assembly.
  • It drafted a new constitution for a German Nation headed by monarchy.
    It failed because King of Prussia joined other monarchs who
    were against parliament.
  • The parliament was dominated by middle classes who resisted the
    demands of workers and artisans. At the end troops were called to
    disband the assembly.

Nationalist Movement In Indo-China

Class X

History

(India and the Contemporary World – II)

Nationalist Movement In Indo-China

Short Type Questions ( 3 Marks )

Q.1 What are the economic barriers to Vietnam identified by Paul Bernard?

Ans

  • High population in Vietnam
  • Low agricultural productivity
  • Extensive indebtedness among
    peasants
  • Lack of industries.

Q.2 Why there aroused difference over the medium of instruction in the school during the French
        reign
in Vietnam?

Ans

  • Some policy makers emphasized the need for French language as the
    medium of instruction
  • By learning French the Vietnamese would familiarize the western culture
  • Asiatic France –Loyal to French Govt.
  • The others suggested for Vietnamese to be taught in lower classes and the French can
    be taught in higher classes
  • Continue their ties with China.

Q.3 How was the school text books reflected in Vietnam during the French Rule?

Ans

  • The text books glorified French and colonial rule
  • The Vietnamese were treated as primitive and backward
  • They are manual labourers and skilled copyists but not creative.

Q.4 What was the role of women in the Anti-Imperial Struggle in Vietnam?

Ans

  • They worked as potters, carried 25kgs of food and war material on their back.
  • They helped the wounded, dug tunnels to save the army
  • They neutralized tens of thousands of bombs and short down many enemy planes
  • They kept open many strategic roads and guarded key points.

Q.5 What were the causes of defeat of French forces in the battle of Dien Bien Phu?

Ans

  • The valley where the French garrisons were located was flooded in the monsoons which made it impossible for the French forces and tanks to move.
  • The whole area was covered with bushes and jungles making it difficult for the French air force to trace anti-aircraft guns hidden in bushes and the jungles.

Long Type Questions ( 5 Marks )

Q.1 The battle against French colonial education became part of the larger battle colonization and        for
       independence. Explain

Ans

  • Teachers and students should not follow the curriculum of French Govt
  • Students fought the colonial efforts to prevent Vietnamese getting white collar job
  • They fought with patriotic feeling
  • Students formed political associations
  • There were protest from different schools

Q.2 What were the causes of US involvement in war in Vietnam?

Ans

  • Foremost was the fear of spread of communism in Vietnam
  • US regarded the spread of communism as a great danger to the capitalist countries
  • The next cause was US entry in Vietnam was an insult that France had to face in Vietnam
  • US wanted to crush Vietnam at all cost to save the prestige of the capitalist countries
  • The Geneva conference had divided Vietnam into 2 parts-North and South Vietnam
  • When Ho Chi Minh government in North Vietnam and National Liberation Front in South
    Vietnam tried to unify the two parts, in violation of Geneva conference, US could not
    tolerate this and hence, she decided to intervene in Vietnam.

Q.3 Explain the role of religious groups in the resistance movement against French Colonialism.

Ans

  • Vietnam was the centre of many religions like Buddhism, Confucianism and local practice
  • The French Missionaries very often destroyed the religious beliefs of Vietnamese
  • Vietnamese-Many religious movements started by Vietnamese
  • The Scholars revolts of 1868 organized by some officials to fight against Christianity
  • Thousands of Catholics were killed
  • Hoa-Hao Movement was very popular movement in Mekong Delta which roused anti-colonial feeling.

Q.4 In Vietnam communist movement was started under Ho Chi Minh

Ans

  • In Vietnam communist movement was started under Ho Chi Minh
  • He founded the Vietnam communist party, Vietminh-the communist waged a series of struggles against USA and France
  • During World war II when Japan attacked Vietnam the communist party of Vietnam bravely fought against both Japan and France and captured Hanoi
  • The North Vietnam Republic was established by Vietminh there after
  • Though French retained its control in south through Bao Dai was also defeated by the
    communists
  • In 1954, as per general agreement the Vietnam was renamed as north and south
    separately under Vietnamese and French respectively
  • But Ho Chi Minh along with NLF fought for an undivided Vietnam
  • With the intension of checking the growth of communism, later USA intervened in Vietnam
  • After defeating US, Vietnam was united under communist rule.

Q.6 What was Phan Chu Trinh’s objective for Vietnam? How were his ideas different from those of
        Phan Boi Chau?

Ans

  • Phan Chu Trinh Phan Boi Chu
    Phan Chu Trinh was a Vietnamese nationalist. He sought to end France’s brutal occupation
    of Vietnam
    Phan Boi Chau was greatly influenced by Confucian ideas
    He was intensely hostile to the monarchy and opposed to the idea of resisting the
    French with the help of the court
    His plan was to use the monarchy and
    the court to drive out the French.
    He was influenced by democratic ideas of the west.  

Nationalism In India

Class X

History

(India and the Contemporary World – II)

Nationalism In India

Short Type Questions ( 3 Marks )

Q.1 Why Non-Cooperation? What was the method used in the Movement?

Ans

  • Gandhi in his famous book Hind Swaraj, declared that the British continue to rule with the
    Cooperation of the Indians
  • If we withdraw our Co-operation then their rule would end. It began
    with surrender of titles, boycott of civil services, army, police, courts and legislative councils,
    schools and foreign goods
  • Swadeshi, Boycott & National education.

Q.2 Why did non-cooperation movement slowdown in cities?

Ans

  • Khadi cloth was more expensive for the poor
  • No alternative Indian Institution to accommodate Indians.
  • Students and teachers began going back to Govt.
    Schools and lawyer joined courts.

Q.3 When did Simon commission come to India? Why was it boycotted?

Ans

  • Simon reached Indian in 1928. It was boycott because- It did not have any single Indian- It did not
    talk about Swaraj

Q.4 Who were the leaders of Khilafat Movement? Why was it started?

Ans

  • Ali brothers – Muhammad Ali and Shaukat Ali.
  • The defeat of Ottoman Turkey in 1st world war-
  • Harsh peace treaty was going to be imposed on Ottoman emperor
  • To defend this, a Khilafat Committee was formed
  • To undo the wrong done to Turkey-Joined with non-cooperation movement

Q.5 What were the conditions of the Gandhi Irwin pact?

Ans

  • Mahatma Gandhi signed the pact with Lord Irwin on 5th March, 1931
  • Gandhi agreed to participate in the 2nd Round table conference in England
  • Government agreed to release all the political
    prisoners.

Q.6 What were the decisions of the Lahore Congress session of 1929?

Ans

  • In December 1929 under the presidency of Jawaharlal Nehru the Lahore Congress formalized the
    demand of ‘Purna Swaraj’ or complete independence.It was declared that 26th January 1930 would be celebrated as the Independence day when people were to take a pledge to struggle for
    independence-Decided to launch Civil Disobedience movement.

Q.7 How did the First World War help in the growth of nationalist movement in India?

Ans

  • War created a new political and economic situation. It led to an increase in expenditure. The war led to a price rise and hardship for common people. War led to forced recruitment of people. Acute Shortage of food led to famine and misery. Indians began to realize that they were drawn in a war unnecessarily. This feeling united Indians against the British.

Long Type Questions ( 5 Marks )

Q.1 “This sense of collective belonging came partly through the experience of united struggles role
         of folklore, songs, icons &images”Analyse the statement.

Ans

  • In late 19th century, Indian Nationalist began recording folk tales sung by bards and toured
    village to gather. The tales they believed gave true picture of traditional culture that was
    damaged by outside forces. It was essential to preserve this folk tradition in order to discover
    the National Identity. It restored a sense of pride in one’s past
  • During Swadeshi Movement, a tricolor flag was designed representing eight provinces
    through eight lotuses and a crescent moon symbolizing Hindu-Muslim unity. Later Gandhiji
    developed tricolor flag (Red, Green and White) with a spinning wheel at center representing
    self-help. Carrying the flag became a symbol of defiance.
  • This image Bharath Mata was first created by Bankim Chandra Chttopadhyay. In 1870 he
    wrote Vande Mataram a hymn to the mother land. Abanindranath Tagore in his painting
    portrayed Bharath Mata as calm, ascetic figure, composed, divine and spiritual

Q.2 Describe the Dandi March of Gandhiji.

Ans

  • Mahatma Gandhi found in salt a powerful symbol that could unite the Nation. He sent letter
    to Viceroy Irwin in which the most stirring was demand to abolish salt tax. When Irwin
    refused, Gandhi started the salt march accompanied by 78 of his trusted volunteers, marched
    240 miles from Sabarmati ashram to Dandi. On his way he told the importance of Swaraj to
    people and asked to defy British. On 6th April he reached Dandi violated the law,
    manufacturing salt by boiling sea water. It marked the beginning of civil disobedience movement

Q.3 Who was Alluri Sitaram Raju? Explain his role in inspiring the rebels with Gandhijis ideas?

Ans

  • Alluri Sitaram Raju was a tribal leader in the Gudem hills of Andhra Pradesh. He started a
    militant Guerilla Movement in the early 1920s. The tribal people were enraged by the British
    policy, but when the government began forcing them to contribute ‘beggar for road building,
    the hill people revolted. Raju inspired the hill people. He talked on the greatness of Mahatma
    Gandhi. Inspired by Gandhijis Non Cooperation Movement he persuaded people to wear
    Khadi and give up drinking. But at the same time he did not believe in Non Violence, he
    thought that India could be liberated only by the use of force.

 

2 thoughts on “CBSE Board Last Year Papers

  1. Alka Srivastava

    Sir you only provided NCERT Solution of only physics and chemestry of class 10 . Please upload more …… Language is understandable to all ……Thank you

    Reply

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