Question

CHEMISTRY

46. Which of the following represents 1 gmolecule of the substance?

(1) 6.02  1024 molecules of NH3 (2) 4 g of helium

(3) 40 g of CaO (4) 127 g of iodine

47. The work function of a metal is 4.2 eV. If radiation of 2000 A falls on the metal, then the

kinetic energy of the fastest photo electrons is

(1) 1.6  1019J (2) 1.6  1010J (3) 3.2  1019J (4) 6.4  1010J

48. Which of the following reactions is a redox reaction?

(1) Cr2O3 + 6HCl  2CrCl3 + 3H2O (2) CrO3 + 2NaOH  Na2CrO4 + H2O

(3) 2 2 2CrO H Cr o OH 4 2 7

       (4) 2 3 Cr O 6I 14H 2Cr 3I 7H O 2 7 2 2

        

49. The conjugate base of (CH3)2 NH2



is :

(1) (CH3)3N (2) (CH3)2NH (3) (CH3)2N



(4) (CH3)2N+

50. Given H2, H2



,

He2



. The correct order of increasing bond energy is

(1) H2< H2



< He2



(2) He2



< H2



< H2 (3) H2



< He2



< H2 (4) H2 < He2

 < H2



51. Carbon tetrachloride has no net dipole moment because of

(1) Its planar structure (2) Its regular tetrahedral structure

(3) Similar sizes of carbon and chlorine atoms

(4) Similar electron affinities of carbon and chlorine

52. Two gas cylinders having same capacity have been filled with 44 g of H2 and 44 g of CO2

respectively. If the pressure in CO2 cylinder is 1 atmosphere at a particular temperature, the

pressure in the hydrogen cylinder at the same temperature is

(1) 44 atmosphere (2) 22 atmosphere (3) 1 atmosphere (4) 2 atmosphere

53. 300 mL of a gas at 27C is cooled to 3C at constant pressure, the final volume is

(1) 270 mL (2) 340 mL (3) 150 mL (4) 240 mL

54. Aluminiumcrystallises in a cubic close-packed structure. Its metallic radius is 125 pm. How

many unit cells are there in 1.00 cm3 of aluminium?

(1) 4.42  1022 (2) 2.36  1021 (3) 2.26  1022 (4) 3.92  1018

55. X-ray analysis shows that the unit cell length in NaCl is 562.8 pm. Calculate the density

you would expect on this basis, NA = 6.023  1023mol1

(1) 0.3216 g cm2 (2) 2.179 g cm1 (3) 1.859 g cm1 (4) 2.346 g cm1

56. Arrange 3 3 3

, ,

   Ce La Pm and 3

Yb in increasing order of their ionic radii

(1) 3 3 3 3

Yb  Pm  Ce  La (2) 3 3 3 3 Ce  Yb  Pm  La

(4) 3 3 3 3

Yb  Pm  La  Ce (4) 3 3 3 3 Pm  La  Ce  Yb

57. The equilibrium constant for the reaction: N2 (g) + 3H2(g) 2NH3 (g) is K and for the

reaction: 2 2 3     1 3 N (g) H g NH g is K

2 2

  K and K will be related to each other as:

(1) K = K (2) K K   (3) K K   (4) K K 1  

58. In the dissociation of PCl5 as PCI5 (g) PCl3(g) + Cl2 (g) if the degree of dissociation is  at

equilibrium pressure P, then the equilibrium constant for the reaction is :

(1)

2

Kp 2

1 p





 

(2)

2 2

p 2

P

K

1





 

(3)

2

p 2

P

K

1





 

(4)

2

p 2

P

K

1





 ​

Answer 1

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