Chemistry Objective Type Questions with Answers for the preparation of Engineering Entrance Test : AIEEE, IIT-JEE, CET
 

(Important For 10+1 & 10+2 Science Students)

Test 8

(1) Elimination of bromine from 2-bromobutane results in the formation of-

(a) equimolar mixture of 1 and 2-butene
(b) predominantly 2-butene
(c) predominantly 1-butene
(d) predominantly 2-butyne

Answer (b) predominantly 2-butene

(2) Equimolar solutions in the same solvent have

(a) Same boiling point but different freezing point
(b) Same freezing point but different boiling point
(c) Same boiling and same freezing points
(d) Different boiling and different freezing points

Answer (c) Same boiling and same freezing points

(3) Which of the following statements in relation to the hydrogen atom is correct?

(a) 3s orbital is lower in energy than 3p orbital
(b) 3p orbital is lower in energy than 3d orbital
(c) 3s and 3p orbitals are of lower energy than 3d orbital
(d) 3s, 3p and 3d orbitals all have the same energy

Answer (d) 3s, 3p and 3d orbitals all have the same energy

(4) The structure of diborane (B2H6) contains

(a) four 2c-2e bonds and two 3c-2e bonds
(b) two 2c-2e bonds and four 3c-2e bonds
(c) two 2c-2e bonds and two 3c-3e bonds
(d) four 2c-2e bonds and four 3c-2e bonds

Answer (a) four 2c-2e bonds and two 3c-2e bonds

(5) Which of the following factors may be regarded as the main cause of lanthanide
contraction?

(a) Poor shielding of one of 4f electron by another in the subshell
(b) Effective shielding of one of 4f electrons by another in the subshell
(c) Poorer shielding of 5d electrons by 4f electrons
(d) Greater shielding of 5d electrons by 4f electrons

Answer (a) Poor shielding of one of 4f electron by another in the subshell

(6) Reaction of cyclohexanone with dimethylamine in the presence of catalytic amount of an acid forms a compound if water during the reaction is continuously removed. The compound formed is generally known as

(a) a Schiff’s base
(b) an enamine
(c) an imine
(d) an amine

Answer (b) an enamine

(7) An amount of solid NH4HS is placed in a flask already containing ammonia gas at a certain temperature and 0.50 atm. Pressure. Ammonium hydrogen sulphide decomposes to yield NH3 and H2S gases in the flask. When the decomposition reaction reaches equilibrium, the total pressure in the flask rises to 0.84 atm. The equilibrium constant for NH4HS decomposition at this temperature is

(a) 0.30
(b) 0.18
(c) 0.17
(d) 0.11

Answer (d) 0.11

(8) Which of the following sets of quantum numbers is correct for an electron in 4f orbital?

(a) n = 4, I =3, m = +4, s = +1/2
(b) n = 3, I = 2, m = -2, S = + 1/2
(c) n =4, I = 3, m = +1, s = + 1/2
(d) n =4, I = 4, m -4, s = - 1/2

Answer (c) n =4, I = 3, m = +1, s = + 1/2

(9) Consider the ground state of Cr atom (Z = 24). The number of electrons with the azimuthal quantum numbers I =1 and 2 are respectively

(a) 12 and 4
(b) 16 and 5
(c) 16 and 4
(d) 12 and 5

Answer (d) 12 and 5

(10) Which one the following ions has the highest value of ionic radius?

(a) Li+
(b) F-
(c) O2-
(d) B3+

Answer (c) O2-

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