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kcet2011-Chemistry- Answer Key

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                             CET – CHEMISTRY – 2011

                                      VERSION CODE: D – 3


    1.   If the energies of the two photons are in the ratio of 3: 2, their wavelengths will be in the
         ratio of
         1) 2: 3                2) 9: 4                     3) 3: 2                  4) 1: 2
    Ans: (1)
                     hc   hc   1    1
          E1: E2 =      :    ⇒    :
                     λ1   λ2   λ1   λ2

                   1    1   λ :λ
          3: 2 =      :    = 2 1          ∴ λ2 : λ1 = 3 : 2 or λ1 : λ2 = 2 : 3
                   λ1   λ2   λ1λ 2



    2.   Which one of these is NOT TRUE for benzene?
         1) It forms only one type of monosubstituted product
         2) There are three carbon-carbon single bonds and three carbon-carbon double bonds
         3) Heat of hydrogenation of benzene is less than the theoretical value
         4) The bond angle between carbon-carbon bonds is 120o
    Ans: (2)
         Benzene doesnot contain 3 single bonds and 3 double bonds. They are all partially double
         due to resonance.


    3.   Generally, the first ionization energy increases along a period. But there are some
         exceptions. The          one which is NOT an exception is…..
         1) Be and B            2) Na and Mg                3) Mg and Al             4) N and O
    Ans: (2)
         I.E. of Mg is more than that of Na. It is not an exception.


    4.   Out of the given two compounds, the vapour pressure of B at a particular temperature is

                                                                                  OH               OH
         1) higher than that of A                                                                       NO2

                                                                                 O                O

         2) lower than that of A
                                                                                  NO2

         3) higher or lower than A depending on the size of the vessel           (A)              (B)



         4) same as that of A
    Ans: (1)
         Vapour pressure of o-nitro phenol is more than vapour presence of p-nitro phenol due to
         intermolecular hydrogen bonding. As a result, it is more volatile.
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    5.   Increasing order of carbon-carbon bond length for the following is
         C2H4                    C2H2                           C6H6                   C2H6
         (A)                     (B)                            (C)                    (D)
         1) C < B < A < D                                       2) B < C < A < D
         3) D < C < A < B                                       4) B < A < C < D
    Ans: (4)
                                                            o
          In C2H6, carbon-carbon bond is single (1.54 A )
                                                                         o
          In C6H6, carbon-carbon bond is partially double (1.39 A )
                                                            o
          In C2H4, carbon-carbon bond is double (1.34 A )
                                                        o
         In C2H2, carbon-carbon bond is triple (1.10 A )


    6.   The IUPAC name of the complex [Co (NH3)4Cl2] Cl is
         1) tetraammine dichloro cobalt (III) chloride
         2) dichloro tetraammine cobalt (III) chloride
         3) tetraammine dichloro cobalt (IV) chloride
         4) tetraammine dichloro cobalt (II) chloride
    Ans: (1)
         IUPAC name of [Co (NH3)4 Cl2] Cl is tetraammine dichloro cobalt (III) chloride


    7.   Excess of silver nitrate solution is added to 100 ml of 0.01 M Pentaaqua chloro chromium (III)
         chloride solution. The mass of silver chloride obtained in grams is
         [Atomic mass of silver is 108]
         1) 143.5 x 10-3         2) 287 x 10-3                  3) 287 x 10-2          4) 143.5 x 10-2
    Ans: (2)
          The reagent is [Cr (H2O)5 Cl] Cl2
                                                 2 x 100 x 0.01
          No. of moles of Cl- ions present =                    = 0.002
                                                      1000
         ∴ Mass of AgCl = 0.002 x 143.5 = 0.287 = 2.87 x 10-3 g


    8.   The following data were obtained during the first order decomposition of 2A(g) → B(g) + C(s) at
         a constant volume and at a particular temperature.

                       Sr. No.                Time                    Total pressure in Pascal

                           1           At the end of 10 min                      300

                           2             After completion                        200


                                    –1
         The rate constant in min        is
         1) 69.3                 2) 0.0693                      3) 6.93 x 10-4         4) 6.93

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    Ans: (2)
           2A (g) → B (g) + C (s)
           2 – 2x               x
           At the end of reaction, only 1 mole of gas is present whose pressure is 200 pascal
           ∴ At the beginning of the reaction 2 moles of gas should have a pressure of 400 pascal
           After time 10 minutes
           No. of moles present, 2 – 2x + x = 2 – x
           The pressure of 2 moles = 400
                          ∴ 400 – x = 300
                                            ∴ x = 100
          ∴ pressure due to 2 – 2x moles of A = 400 – 200 = 200
                      2.303     ⎛ a ⎞     2.303     ⎛ 400 ⎞   2.303         0.693
          ∴k=               log ⎜     ⎟ =       log ⎜     ⎟ =       log 2 =       = 0.0693 min-1
                        t       ⎝ a− x⎠    10       ⎝ 200 ⎠    10            10



    9.    The time required for 100% completion of a zero order reaction is
                a                                                        2k         a
          1)                                2) ak                   3)         4)
               2k                                                         a         k
    Ans: (4)
                                                           a
          Half life of a zero order reaction =
                                                          2k
                                                                a   a
          Time taken for completion = 2t1/2 = 2 x                 =
                                                               2k   k


    10.   The activation energy of a reaction at a given temperature is found to be 2.303 RT J mol – 1.
          The ratio of rate constant to the Arrhenius factor is
          1) 0.1                            2) 0.01                 3) 0.001   4) 0.02
    Ans: (1)
                          Ea
                      −
          k = Ae          RT

                          Ea
          k    −
            = e RT
          A
               ⎛k ⎞            −Ea
          ln ⎜ ⎟ =
               ⎝A⎠             RT

                               ⎛k ⎞   −Ea
          2.303 log ⎜ ⎟ =
                               ⎝A⎠    RT

                ⎛k ⎞               −Ea
          log ⎜ ⎟ =
                ⎝A⎠             2.303 RT

                ⎛k ⎞            −2.303 RT
          log ⎜ ⎟ =
                ⎝A⎠             2.303 RT

                ⎛k ⎞                            k
          log ⎜ ⎟ = -1                      ∴     = 0.1
                ⎝A⎠                             A

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    11.   The yellow precipitate formed during the chromyl chloride test is chemically
          1) lead chromate                                 2) chromic acid
          3) sodium chromate                               4) lead acetate
    Ans: (1)
          Chromyl chloride + water + lead acetate → lead chromate


    12.   One gram of silver gets distributed between 10 cm3 of molten zinc and 100 cm3 of molten
          lead at 800oC. The percentage of silver still left in the lead layer is approximately
          1) 5                      2) 2                   3) 1                   4) 3
    Ans: (4)
                                    Conc. of Ag in molten Zn
          Partition coefficient =
                                    Conc. of Ag in molten Pb

          Mass of Ag in lead at equilibrium = 1 – x
          Mass of Ag in Zn at equilibrium = x
                     x / 10     10 x
          300 =               =
                  1 − x / 100   1−x

          10x = 300 – 300x
          310x = 300
                 300   30
          x=         =
                 310   31
                                                          30   1                1
          Amount of silver in molten lead = 1 – x = 1 -      =    ∴ of silver =    x 100 = ≃ 3%
                                                          31   31               31


    13.   Which one of the following is true?
          1) NaOH is a primary standard in volumetric analysis
          2) NaOH is used in the concentration of bauxite ore
          3) NaOH solution does not react with Cl2
          4) Manganous hydroxide is soluble excess of NaOH solution
    Ans: (2)


    14.   In Ramsay and Rayleigh’s isolation of noble gases from air, the nitrogen of the air is finally
          converted into
          1) NO and NO2             2) NaNO2 only          3) NaNO2 and NaNO3 4) NaNO3 only
    Ans: (3)


    15.   The spin only magnetic moment of Fe2+ ion (in BM) is approximately
          1) 7                      2) 4                   3) 6                   4) 5
    Ans: (4)
          Fe+2 : [Ar] 3d6
          It has 4 unpaired electrons ∴ μ = n (n + 2) =        4 (4 + 2) =   24 = 4.89 BM

          ∴ ≃ 5 BM
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    16.   A mixture of CaCl2 and NaCl weighing 4.44 g is treated with sodium carbonate solution to
          precipitate all the calcium ions as calcium carbonate. The calcium carbonate so obtained is
          heated strongly to get 0.56 g of CaO. The percentage of NaCl in the mixture is
          [Atomic mass of Ca = 40]
          1) 75                      2) 31.5                  c) 40.2            d) 25
    Ans: (1)
          CaO ← CaCO3 ← CaCl2
          0.56 g     1g          1.12 g
          ⎡ 56 − 100⎤         ⎡100 → 112 ⎤
          ⎢          ⎥        ⎢          ⎥
          ⎣0.56 − 1g ⎦        ⎣ 1g → 1.12⎦
          ∴ Amt of NaCl = 4.44 – 1.12 = 3.32
                           3.32
          % of NaCl =           x 100 = 75
                           4.44


    17.   50 cm3 of 0.2 N HCl is titrated against 0.1 N NaOH solution. The titration was discontinued
          after adding 50 cm3 of NaOH. The remaining titration is completed by adding 0.5 N KOH.
          The volume of KOH required for completing the titration is
          1) 12 cm3                  2) 10 cm3                3) 21.0 cm3        4) 16.2 cm3
    Ans: (2)
          No. of equivalents of HCl remaining after adding 50 cm3 of 0.1 N NaOH =
          0.2 x 50 − 0.1 x 50   0.5
                              =
                 100            100
                                                 0.5      V x 0.5
          ∴ Volume of 0.5 N KOH required             eq ≡
                                                 100      1000
                0.5 1000
          V=        x     = 10 cm3
                100   0.5


    18.   The rms velocity of hydrogen is 7 times the rms velocity of nitrogen. If T is the
          temperature of the gas, which of the following is true?
          1) TH2 =      7 TN2        2) TN2 = TH2             3) TN2 =   7 TH2   4) TN2 = 2 TH2

    Ans: (4)
          CH2              TH2 x28
                = 7 =
          CN2              2 x TN2

                   14TH2
          or 7 =            or TN2 = 2TH2
                    TN2



    19.   25 g of each of the following gasses are taken at 27oC and 600 mm pressure. Which of these
          will have the least volume?
          1) HCl                     2) HBr                   3) HI              4) HF
    Ans: (3)
          HI has the least number of moles. Therefore volume occupied is least.

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    20.   The amount of heat evolved when 500 cm3 of 0.1 M HCl is mixed with 200 cm3 of 0.2 M NaoH
          is
          1) 2.292 kJ                2) 1.292 kJ              3) 22.9 kJ           4) 0.292 kJ
    Ans: (1)
                                                        40
          No. of equivalents of NaOH reacting =
                                                       1000
          1 eq → 57.3
           40
               eq → ?       i.e. 2.292 kJ
          1000


    21.   pH value of which one of the following is NOT equal to one?
          1) 0.1 M HNO3                                       2) 0.1 M CH3 COOH
          3) 50 cm3 0.4 M HCl + 50 cm3 0.2 M NaOH             4) 0.05 M H2SO4
    Ans: (2)
          0.1 M CH3COOH is not completed dissociated. Therefore pH will not be one.


    22.   A buffer solution contains 0.1 mole of sodium acetate dissolved in 1000 cm3 of 0.1 M acetic
          acid. To the above buffer solution, 0.1 mole of sodium acetate is further added and dissolved.
          The pH of the resulting buffer is ………
          1) pKa + 1                 2) pKa                   3) pKa + Log 2       4) pKa = Log 2
    Ans: (3)
                            [Salt]
          pH = pKa + log
                            [Acid]

          When extra 0.1 mole sodium acetate is added [Salt] = 0.2 mol dm-3
          [Acid] = 0.1 mol dm-3
          ∴ pH = pKa + log 2
    23.   H2S is passed into one dm3 of a solution containing 0.1 mole of Zn2+ and 0.01 mole of Cu2+ till
          the sulphide ion concentration reaches 8.1 x 10 – 19 moles. Which one of the following
          statements is true? [Ksp of ZnS and CuS are 3 x 10 – 22 and 8 x 10 – 36 respectively]
          1) Both CuS and ZnS precipitate                     2) Only ZnS precipitates
          3) No precipitation occurs                          4) Only CuS precipitates
    Ans: (1)
          The ionic product for ZnS (0.1 x 8.1 x 10-19) and for CuS (0.01 x 8.1 x 10-19) exceeds their Ksp
          values. Hence both get precipitated.


    24.   E1, E2 and E3 are the emfs of the following three galvanic cells respectively:
          (i) Zn (s) |Zn2+ (0.1 M)|| Cu2+ (1M) | Cu (s)
          (ii) Zn (s) |Zn2+ (1 M)|| Cu2+ (1M) | Cu (s)
          (iii) Zn (s) |Zn2+ (1 M)|| Cu2+ (0.1M) | Cu (s)
          Which one of the following is true?
          1) E1 > E2 > E3            2) E2 > E1 > E3          3) E3 > E2 > E1      4) E3 > E1 > E2

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    Ans: (1)
                     0.059     [Cu2 + ]
          E = Eo +         log          ∴ E1 > E2 > E3
                       2       [Zn2 + ]


    25.   0.023 g of sodium metal is reacted with 100 cm3of water. The pH of the resulting solution is
          …………
          1) 8                      2) 10                  3) 12                     4) 9
    Ans: (3)
          2Na + 2H2O → 2 NaOH + H2
          2 x 23           2 x 40
          0.023            0.04
                      0.04
          ∴ [OH-] =        x 10 = 10 − 2        pOH = 2    ∴ pH = 12
                       40


    26.   Which one of the following statements is FALSE?
          1) The ore is freed from almost all nonmetallic impurities.
          2) During roasting, moisture is removed from the ore.
          3) The concentrated zinc blende is subjected to calcinations during its extraction by
          pyrometallurgy.
          4) Calcination of ore is carried out in the absence of any blast of air.
    Ans: (3)
          In pyrometallurgy of Zn, ZnS is subjected to roasting.


    27.   Which one of the following sets of quantum numbers represents the highest energy level in
          an atom?
                                            1                                               1
          1) n = 3, l = 1, m = 1, s = +                    2) n = 4, l = 0, m = 0, s = +
                                            2                                               2
                                            1                                               1
          3) n = 3, l = 0, m = 0, s = +                    4) n = 3, l = 2, m = -2, s = +
                                            2                                               2
    Ans: (4)
          ‘n + l ’ = 3 + 2 = 5
          Represents 3d shell which is the highest energy level.


    28.   When O2 is converted into O2 ; …………
                                     +




          1) bond order decreases
          2) both paramagnetic character and bond order increase
          3) paramagnetic character decreases and the bond order increases
          4) paramagnetic character increases
    Ans: (3)
          O2 contains 2 unpaired electrons in ABMO, Bond order = 2
          O2+ contains 1 unpaired electron in ABMO, Bond order = 2.5

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    29.   In chromite ore, the oxidation number iron and chromium are respectively ……..
          1) +3, +6                 2) +3, +2             3) +2, +3            4) +2, +6
    Ans: (3)
          Chromite ore FeCr2O4 i.e. FeO Cr2O3
          O.N. of Fe = +2; O.N. of Cr = +3


    30.   The number of naturally occurring p-block elements that are diamagnetic is ………….
          1) 6                      2) 18                 3) 7                 4) 5
    Ans: (4)
          The group 18 elements have completely filled subshells. They are diamagnetic.
          They are He, Ne, Ar, Kr & Xe.


    31.   The enthalpy of vaporization of benzene is + 35.3 kJ/mol at its boiling point of 800 C. The
          entropy change in the transition of vapour to liquid at its boiling point is ……….
                      –1       –1
          [in J mol        K    ]
          1) + 100                  2) – 100              3) – 342             4) + 342
    Ans: (2)
          ΔH = +35.3 kJ/mol
          T = 80oC = 80 + 273 = 353 K
                 ΔH   +35.3
          ΔS =      =       = 0.1 kJ
                  T    353
          ΔS = 0.1 x 103 J/mol/K
          Entropy change in the transition of vapour to liquid is negative.
          ΔS = -100


    32.   Based on the first law of thermodynamics, which one of the following is correct?
          1) For an isochoric process, ΔU = -q            2) For an isochoric process, q = +w
          3) For a cyclic process, q = -w                 4) For an adiabatic process, ΔU = -w
    Ans: (3)
          First law of thermodynamics, Δu = q + w
          Change in internal energy for cyclic process is 0
          ∴ q = -w


    33.   Consider the following gaseous equilibria with equilibrium constants K1 and K2 respectively.
                      1
          SO2 (g) +     O2 (g) ⇌ SO3 (g)
                      2

          2SO3 (g) ⇌ 2SO2 (g) + O2 (g)
          The equilibrium constants are related as ……….
                      1                                             2                     1
          1) K 1 =
               2
                                    2) 2K1 = K 2
                                               2          3) K2 =              4) K 2 =
                                                                                    2
                      K2                                            K1
                                                                     2
                                                                                          K1
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    Ans: (1)
                           1
          SO2 (g) +          O2 (g) ⇌ SO3 (g)             - (1) K1
                           2
          Equation (1) is reversed and multiplied by 2
          2SO3 (g) ⇌ 2SO2 (g) + O2 (g)                    - (2) K2
                       1
          ∴ K2 =    2
                   K1

                  1
          K12 =
                  K2


    34.   During the adsorption of Krypton on activated charcoal at low temperature; ………….
          1) ΔH > 0 and ΔS < 0 2) ΔH < 0 and ΔS < 0
          3) ΔH < 0 and ΔS > 0 4) ΔH > 0 and ΔS > 0
    Ans: (2)
          During adsorption heat is liberated hence ΔH is negative (less than zero) and entropy
          decreases


    35.   For the reversible reaction, A(s) + B(g) ⇌ C(g) + D(g) ΔG0 = -350 kJ, which one of the following
                                                B




          statements is true?
          1) The entropy change is negative
          2) The reaction is thermodynamically nonfeasible
          3) The reaction should be instantaneous
          4) Equilibrium constant is greater then one.
    Ans: (4)
          A (s) + B (g) ⇌ C (g) + D (g)                   ΔGo = -350 kJ
          Relationship between ΔGo and equilibrium constant is
          ΔGo = -2.303 RT log Kp
          When Kp > 1, ΔG0 is negative


    36.   Identify B and D is the following sequence of reactions.


                                                         CH2 = CH2            Conc. H2SO4
                                                                                                   A
          1) Ethyl hydrogen sulphate and
            alcoholic KOH
                                                            D                                     Δ        H2O
          2) Methanol and bromoethane
                                                                                                       B
                                                                C
          3) Ethanol and alcoholic KOH


          4) Ethyl hydrogen sulphate and aqueous KOH

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    Ans: (3)
                     Conc H SO4
          CH2 = CH2 ⎯⎯⎯.⎯2⎯⎯ → CH5 – CH2 – HSO4 (A) (addition reaction)
                              ⎯
                         Δ HO
          CH3CH2 – HSO4 ⎯⎯,⎯2⎯ → CH3CH2 – OH (B)
                             ⎯                            (hydrolysis)
                       PBr3
          CH3CH2 – OH ⎯⎯⎯ → CH3CH2 – Br (C) (bromination)
                          ⎯
                       alco. KOH (Δ)
          CH3CH2 – Br ⎯⎯⎯⎯⎯⎯ → CH2 = CH2 (dehydro halogenation)
                                   ⎯


    37.   The compound which gives turbidity immediately with Lucas reagent at room temperature is
          ………
          1) butan-2-ol                                   2) butan-1-ol
          3) 2-methyl propan-1-ol                         4) 2-methyl propan-2-ol
    Ans: (4)
          2-methyl propan-2-ol is an example for tertiary alcohol. Tertiary alcohol gives turbidity
          immediately with lucas reagent


    38.   Ethyl benzene CANNOT be prepared by ……….
          1) Wurtz-Fittig reaction                        2) Wurtz reaction
          3) Clemmensen reduction                         4) Friedel-Crafts reaction
    Ans: (2)
          In Wurtz reaction haloalkanes are converted to aliphatic saturated higher hydrocarbons.


    39.   1.2 g of organic compound on Kjeldahilization liberates ammonia which consumes 30 cm3 of
          1 N HCl. The percentage of nitrogen in the organic compound is ………..
          1) 35                   2) 30                   3) 20.8               4) 46.67
    Ans: (1)
                              1.4 x Normality of acid x Volume used with NH3 1.4 x 1 x 30
    Percentage of Nitrogen=                                                 =             =35
                                       weight of organic compound                1.2


    40.   Carbon cannot reduce Fe2O3 to Fe at a temperature below 983 K because ………
          1) CO is thermodynamically more stable then Fe2O3
          2) free energy change for the formation of CO is more negative then that of Fe2O3
          3) iron has higher affinity towards oxygen then carbon
          4) carbon has higher affinity towards oxygen then iron
    Ans: (3)
                              0
                                                       Fe2O3
                           -200
                           -400
                   ΔGo                              2C + O2 → 2CO
                  kJ/mol   -600
                           -800

                                     500 983 K
                                                  Temp (K)
          Below 983 K, conversion of Iron to ferric oxide is more favourable.

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    41.     Which one of the following is NOT TRUE for the hydrolysis of t-butyl bromide with aqueous
            NaOH?
            1) The intermediate formed is a carbocation.
            2) Reaction occurs through the SN1 mechanism.
            3) Rate of the reaction doubles when the concentration of t-butyl bromide is doubled
            4) Rate of the reaction doubles when the concentration of alkali is doubled.
    Ans: (4)
            Hydrolysis of t-butyl bromide with aqueous NaOH is an example for SN1 reaction, rate of the
            reaction depends only on concentration of haloalkane.
            Rate ∝ [Haloalkane]
    42.     Following is the substitution reaction in which ⎯CN replaces ⎯Cl

             R - Cl      +      KCN             R - CN + KCl
                             (alcoholic)   Δ

            To obtain propanenitrile, R-Cl should be
            1) 1- chloropropane                                     2) chloroethane
            3) 2-chloropropane                                      4) chloromethane
    Ans: (2)
            C2H5Cl + KCN → C2H5CN + KCl
    43.     The conversion of m-nitrophenol to resorcinol involves respectively
            1) diazotization, reduction and hydrolysis
            2) hydrolysis, diazotization and reduction
            3) reduction, diazotization and hydrolysis
            4) hydrolysis, reduction and diazotization
    Ans: (3)

     OH                               OH                       OH                              OH
                                                 0 - 5oC
                       [H]                       HNO2                              H2O
     O                                O                        O                               O           +   N2   + HCl
                                                                      N   N   Cl                      OH
                 NO2                           NH2

    44.     Formic acid is a stronger acid than acetic acid. This can be explained using
            1) –I effect                   2) +M effect             3) –M effect            4) +I effect
    Ans: (4)
                 O
    H3C          C     OH , methyl group is a electron releasing group in acetic acid
          ‘+I’

    45.     The reagent with which both acetaldehyde and acetone react is
            1) I2/NaOH                                              2) Fehling’s reaction
            3) Carbonic acid                                        4) Tollen’s reagent



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    Ans: (1)
                                   O                                   O                                        O
          Acetaldehyde                         and acetone                            due to presence of H C    C
                           H3C     C       H                 H3C       C        CH3                       3


          group reacts with iodine in sodium hydroxide to give yellow crystals of iodoform.


    46.   The standard emf of a galvanic cell involving 2 moles of electrons in its rodox reaction is 0.59
          V. The equilibrium constant for the redox reaction of the cell is
          1) 105                   2) 1020                   3) 1010                      4) 10
    Ans: (2)
          In a galvanic cell, ΔGo = -nFEo                    - (1)
                                       o
          Relationship between ΔG and equilibrium constant
                                   ΔGo = -2.303 RT log kp - (2)
          From (1) and (2)
          -2.303 RT log kp = -nFEo
                        nFEo       nEo      2 x 0.59
          log kp =             =          =          = 20
                      2.303 RT   2.303 RT    0.059
                                    F
          kp = A . L (20) = 2020


    47.   9.65 coulombs of electric current is passed through fused anhydrous MgCl2. The magnesium
          metal thus obtained is completely converted into a Grignard reagent. The number of moles of
          Grignard reagent obtained is
                      –4                       –4                          –5                         –5
          1) 1 x 10                2) 5 x 10                 3) 1 x 10                    4) 5 x 10
    Ans: (4)
          96500 coulombs of electric current deposits 12 g of magnesium 9.65 coulombs of electric
                             9.65 x 12
          current deposits             = 1.2 x 10-3 g of magnesium
                               96500
                                                                                1.2 x 10 −3
          ∴ The number of moles of Grignard reagent obtained is =                             = 0.05 x 10-4
                                                                                    24
                                                                                                           –5
                                                                                              = 5 x 10


    48.   The empirical formula of a nonelectrolyte is CH2O. A solution containing 3g of the compound
          exerts the same osmotic pressure as that of 0.05 M glucose solution. The molecular formula
          of the compound is
          1) C2H4O2                2) CH2O                   3) C3H6O3                    4) C4H8O4
    Ans: (1)
          For isotonic solution (solution with same osmotic pressure) c1 = c2
          Wx   WC6H12O6
             =
          Mx   MC6H12O6

          3     9
             =
          Mx   180


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          0.05 M C6H12O6 containing 9 g of glucose
                   3 x 180
          Mx =             = 60
                      9
          Molecular weight of a nonelectrolyte is 60
          Molecular formula = n x empirical formula
          Empirical formula = CH2O
          Empirical formula mass = 12 + 2 + 16 = 30
                  molecularmass         60
          n=                          =    =2
               Empirical formula mass   30

          Molecular formula = 2 x CH2O = C2H4O2
    49.   Which one of the following is a covalent crystal?
          1) Ice                       2) Rock salt                3) Dry ice           4) Quartz
    Ans: (4)
          Lattic points mode up of nonmetal, they are held by covalent bond.


    50.   Which one of the following DOES NOT involve coagulation?
          1) Formation of delta region
          2) Clotting of blood by the use of ferric chloride
          3) Peptization
          4) Treatment of drinking water by potash alum
    Ans: (3)
          Peptization is process in which freshly formed precipitate converted to colloidal sol by adding
          suitable electrolyte (peptizing agent)


    51.   Which of the following gives an aldehyde on dry distillation?
          1) Calcium acetate + calcium benzoate                    2) Calcium formate + calcium acetate
          3) Calcium benzoate                                      4) Calcium acetate
    Ans: (2)
                                                 0
          (HCOO)2 Ca + (CH3COO)2 ⎯⎯⎯ → 2 CH3CHO + 2CaCO3
                                      ⎯
                                  400 C




    52.   α - maltose consists of
          1) two α-D-glucopyranose units with 1-2 glycosidic linkage
          2) one α-D-glucopyranose units and one β-D-glucopyranose unit with 1-2 glycosidic linkage
          3) two α-D-glucopyranose units with 1-4 glycosidic linkage
          4) two β-D-glucopyranose units with 1-4 glycosidic linkage
    Ans: (3)
                         CH2OH                             CH2OH
                 H                     H             H
                             O                                      O    H
                      H          H 1                     4 H        H
                     OH                                    OH
                                                                         OH
               HO
                                             O
                     H           OH                       H         OH
                                                                                                          13
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           In maltose Ist carbon atom of one L – D (+) glucose unit is linked to 4th carbon atom of
           adjacent glucose unit through glycosidic linkage


    53.   Which one of the following DOES NOT correctly match with each other?
          1) Lipase-enzyme           2) Silk-polyamide         3) Oxytocin-enzyme 4) Butter-fat
    Ans: (3)
          Oxytocin is an example for hormone (biochemical messengers)


    54.   In an alkaline medium, glycine predominantly exists as/in a /an
          1) anion                   2) cation                 3) covalent form       4) zwitterions
    Ans: (1)
           In alkaline medium (high pH) amino acids exists as negatively charged particle (carboxyl
           group donates proton).
                                                               −
          H2N – CH2 – COOH ⎯⎯ ⎯⎯→ H2N – CH2 - CO O
                            High pH




    55.   The IUPAC name of                      O        is


          1) but-1-enoic acid                        OH
                                                               2) but-3-enoic acid
          3) prop-2-enoic acid                                 4) pent-4-enoic acid
    Ans: (2)
                                        O

               H2C      CH      CH2     C    OH                    Root word: But -
                         3       2      1
                4                                                  Suffix: (10) 3 – ene
                                                                          (20) oic acid
                                                                   IUPAC Name: But – 3 – enoic acid

            Bond line natation of the above compound
                          O


                                OH



    56.   A solution of two liquids boils at a temperature more than the boiling point of either of them.
          Hence, the binary solution shows
          1) positive deviation from Raoult’s law
          2) negative deviation from Raoult’s law
          3) positive or negative deviation from Raoult’s law depending upon the composition
          4) no deviation from Raoult’s law
    Ans: (2)
          Solutions boil at relatively higher temperature, vapour pressure of solution is less

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                                                                 O

    57.   Which one of the nitrogen atoms in H2N         NH      C     NH2    is the most nucleophilic?
                                                    I    II            III
          1) I
          2) III
          3) All three nitrogen atoms are equally strong nucleophilic centers
          4) II
    Ans: (1)


    58.   The maximum number of possible isomers in 1-bromo-2-methyl cyclobutane is
          1) 2                          2) 4                  3) 16                 4) 8
    Ans: (2)
                                H
                   H2C          C       CH3
                            2                     Number of asymmetric c-atoms = (n) = 2
                            1                     ∴ Total number of optical isomers = 2n = 22 = 4
                   H2C       C          Br
                                H



    59.   Which one of the following is the most energetic conformation of cyclohexane?
          1) Twisted boat               2) Boat               3) Half chair        4) Chair
    Ans: (3)


           Most energetic conformation (least stable) of cyclohexane is half chair form



    60.   Which one of the following is an intermediate in the reaction of benzene with CH3Cl in the
          presence of anhydrous AlCl3?
                                                                 +
               −
          a) CH3                2) Cl+                    3)                   4) CH3 +


    Ans: (4)
                                    +
           Ch3Cl + AlCl3 → C H3 + AlC l4
                                       −




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