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Chemistry 13_Objective_Phase I to VI_Paper_3

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PAPER – IV

 

 

  1. Photoelectric emission is observed from a surface for frequencies n1 and n2 of the incident radiation (n1 > n2). If the maximum kinetic energies of the photoelectrons in the two cases are in the ratio 1 : k then the threshold frequency no is given by

(A)                                       (B)

(C)                                                    (D)

 

  1. Energy levels A, B, C of a certain atom corresponds to increasing values of energy i.e.
    EA < EB < EC. If l1, l­2 and l3 are the wavelengths of radiations corresponding to the transitions C to B, B to A and C to A respectively, which of the following statement is correct.

 

(A) l3 = l1 + l2                                               (B) l3 =

(C) l1 + l­2 + l3 = 0                                         (D) l32 = l12 + l22

 

  1. Three isotopes of an element have mass numbers, M, (M+1) and (M+2). If the mean mass number is (M + 0.5) then which of the following ratios may be accepted for M, (M + 1),
    (M + 2) in that order

(A) 1 : 1 : 1                                                      (B) 4 : 1 : 1

(C) 3 : 2 : 1                                                      (D) 2 : 1 : 1.

 

  1. When photons of energy 4.25 eV strike the surface of a metal A, the ejected photoelectrons have maximum kinetic energy, TA (expressed in eV) and de Broglie wavelength lA. The maximum kinetic energy of photoelectrons liberated from another metal B by photons of energy 4.20 V is TB = TA – 1.50 eV. If the de-Broglie wavelength of these photoelectrons is
    lB = 2lA, then

(A) the work function of A is 2.25 eV             (B) the work function of B is 4.20 eV

(C) TA = 2.00 eV                                             (D) TB = 2.75 eV.

 

  1. 0.7 g of a sample of Na2CO3×xH2O were dissolved in water and the volume was made to 100 ml, 20 ml of this solution required 19.8 ml of N/10 HCl for complete neutralization. The value of x is

(A) 7                                                                (B) 3

(C) 2                                                                (D) 5

 

  1. Which graph correctly correlates Ecell as a function of concentrations for the cell (for different values of M and M¢)

Zn(s) + Cu+2 (M) ¾® Zn2+(M¢) + CuS; E0cell = 1.10 V

X axis: log10 , Y axis; Ecell

            (A) (B)
            (C) (D)

 

  1. A hydrogen electrode placed in a buffer solution of CH3COONa and acetic acid in the ratio’s x:y and y:x has electrode potential values E1 volts and E2 volts respectively at 25oC. The pKa values of acetic acid is (E1 & E2 are oxidation potential).

(A)                                                    (B) 0

(C)                                                (D)0

 

  1. A 0.518 g sample of limestone is dissolved in HCl and then the calcium is precipitated as CaC2O4. After filtering and washing the precipitate, it requires 40.0 mL of 0.250 N KMnO4, solution acidified with H2SO4 titrate as, MnO4 + H+ + C2O42– ¾® Mn2+ + CO2 + 2H2O. The percentage of CaO in the sample is

(A) 54.0%                                                        (B) 27.1%

(C) 42%                                                           (D) 84%

 

  1. An element A in a compound ABD has oxidation number An–. It is oxidised by Cr2O72– in acid medium. In the experiment 1.68 ´ 10–3 moles of K2Cr2O7 were used for 3.26 ´ 10–3 moles of ABD. The new oxidation number of A after oxidation is.

(A) 3                                                                (B) 3 – n

(C) n – 3                                                          (D) + n

 

  1. At 40oC the vapour pressures in torr, of methyl alcohol – ethyl alcohol solutions is represented by the equation. P = 119XA + 135 where XA is mole-fraction of methyl alcohol, then the value of is

(A) 254 torr                                                      (B) 135 torr

(C) 119 torr                                                     (D) 140 torr

 

  1. A substance undergoes first order decomposition. The decomposition follows two parallel first order reactions as:

 

The percentage distribution of B and C are:

(A) 80% B and 20% C                                          (B) 76.83% B and 23.17% C.

(C) 90% B and 10% C                                          (D) 60% B and 40% C

 

  1. Calculate the molal elevation constant of water which evaporates at 100°C with absorption of 536 cal/gm

(A) 0.519°                                                        (B) 0.612°

(C) 0.915°                                                       (D) 0.621°

 

  1. A radioactive isotopes decays at such a rate that after 96 minutes only 1/8th of the original amount remains. The t1/2 of the nuclei is

(A) 12 minutes                                                (B) 32 minutes

(C) 24 minutes                                                (D) 48 minutes

 

  1. The root mean square velocity of an ideal gas is given by the expression

 

When the pressure is doubled at constant temperature

(A) Ur.m.s. increases Ö2 times                          (B) Ur.m.s. is doubled

(C) Ur.m.s. remains unchanged                        (D) Ur.m.s. increases by three times

 

 

  1. The shape of [Cu(NH3)4]2+ is square planar, Cu2+ in this complex is

(A) sp3 hybridised                                           (B) dsp2 hybridised

(C) sp3d hybridised                                         (D) sp3 d2 hybridised

 

  1. Prussian blue is formed when

(A) ferrous sulphate reacts with FeCl3

(B) ferric sulphate reacts with K4[Fe(CN)6]

(C) ferrous ammonium sulphate reacts with FeCl3

(D) ammonium sulphate reacts with FeCl3

 

  1. Concentrated NaOH can separate a mixture of

(A) Al3+ and Cr3+                                             (B) Cr3+ and Fe3+

(C) Al3+ and Zn2+                                             (D) Zn2+ and Pb2+

 

  1. The hybridisation of boron in orthoboric acid is

(A) sp3                                                             (B) sp2

(C) sp                                                              (D) sp3d

 

  1. In concentrated sodium thiosulfate solution silver nitrate gives

(A) white ppt of Ag2S2O3                                (B) soluble complex of Na3[Ag(S2O3)2]

(C) Black ppt of Ag2S                                     (D) black ppt of Ag.

 

  1. Which complex is diamagnetic

(A) [Fe(CN)6]4–                                               (B) [Cu(NH3)4]2+

(C) [Ti(H2O)6]3+                                               (D) None

 

  1. Which of the following pairs of isomers and types of isomerism are correctly matched
  2. [Co(NH3)5(NO2)]Cl2 and [Co(NH3)5(ONO)]Cl2 ……..linkage
  3. [Cu(NH3)4] [PtCl4] and [Pt(NH3)4][CuCl4] —— Coordination
  4. [Pt(NH3)4Cl2]Br2 and [Pt(NH3)4Br2]Cl2.. Ionization

(A) 2 and 3                                                      (B) 1,2 and 3

(C)  1 and 3                                                     (D) 1 and 2

 

  1. 3, 5-dimethylcyclopentene Identify major product.
            (A) (B)
            (C) (D)

 

  1. CH2 = CH – CN Z is major product. So Z is
            (A) (B)
            (C) (D) EtO – CH2 – CH2 – CN

 

  1. Which of the following compound is optically active?
            (A) CH2 = C = CH – Me (B)
            (C) (D)

 

85.
            (A) (B)
            (C) (D)

 

  1. PhCHO + MeCHO

(A) Ph – CH = CH – CH2OH                          (B) Ph – CH2CH2 – CH2OH

(C) Ph – CH2 – CH2 –– OH                        (D) None

 

 

87.
            (A) (B)
            (C) (D)

 

  1. Cyclooctatetraene is not aromatic. The reason for this is that

(A) It has eight p electrons

(B) It is a planar molecule

(C) Its structure is not that of a regular octagon

(D) Its structure can not be described by more than two canonical forms

 

  1. Which of the following compounds can be optically active
            (A) (B)
            (C) CH2 = CH – CH3 (D)

 

  1. Consider the following pairs of compounds
            a)
            b)

of these pairs

(A) Both a and b are resonance forms

(B) both a and b are tautomeric forms

(C) A is a resonance pair while B is a pair of tautomers

(D) A is a pair of tautomers while B is a resonance pair

Answers

  1. B                                         

.                 62.       B                                          63.       B                                                      64.       D        

  1. C                                          66.       B                                                      67.       A        
  2. 68. A                                                 B                                                      70.       A        
  3. B                                          72.       A                                                      73.       B        
  4. C                                          75.       B                                                      76.       B        
  5. B                                          78.       B                                                      79.       B        
  6. A                                          81.       B                                                      82.       A        
  7. 83. D                                          84.       D                                                             D        
  8. A                                          87.       C                                                      88.       A        
  9. D                                          90.       C
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