Chemistry entrance exam for online practice

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

(1) In which of the following molecules/ions are all the bonds not equal?

(a) SF4
(b) SiF4
(c) XeF4
(d) 4 BF−

Answer (a) SF4

(2) Which one of the following sets of ions represents a collection of isoelectronic species?

(a) K+ , Cl–, Ca2+, Sc3+
(b) Ba2+, Sr2+, K+, S2–
(c) N3–, O2–, F–, S2–
(d) Li+, Na+, Mg2+, Ca2+

Answer (a) K+ , Cl–, Ca2+, Sc3+

(3) What products are expected from the disproportionation reaction of hypochlorous acid?

(a) HClO3 and Cl2O
(b) HClO2 and HClO4
(c) HCl and Cl2O
(d) HCl and HClO3

Answer (d) HCl and HClO3

(4) In Fe(CO)5, the Fe – C bond possesses

(a) π-character only
(b) both σ and π characters
(c) ionic character
(d) σ-character only

Answer (b) both σ and π characters

(5) Lanthanoid contraction is caused due to

(a) the appreciable shielding on outer electrons by 4f electrons from the nuclear charge
(b) the appreciable shielding on outer electrons by 5d electrons from the nuclear charge
(c) the same effective nuclear charge from Ce to Lu
(d) the imperfect shielding on outer electrons by 4f electrons from the nuclear charge

Answer (d) the imperfect shielding on outer electrons by 4f electrons from the nuclear charge

(6) In Langmuir’s model of adsorption of a gas on a solid surface

(a) the rate of dissociation of adsorbed molecules from the surface does not depend on the surface covered
(b) the adsorption at a single site on the surface may involve multiple molecules at the same time
(c) the mass of gas striking a given area of surface is proportional to the pressure of the gas
(d) the mass of gas striking a given area of surface is independent of the pressure of the gas

Answer (c) the mass of gas striking a given area of surface is proportional to the pressure of the gas

(7) Rate of a reaction can be expressed by Arrhenius equation as:
k = Ae−E/RT (where E/RT is read as power of e) In this equation, E represents

(a) the energy above which all the colliding molecules will react
(b) the energy below which colliding molecules will not react
(c) the total energy of the reacting molecules at a temperature, T
(d) the fraction of molecules with energy greater than the activation energy of the reaction

Answer (b) the energy below which colliding molecules will not react

(8) Reaction of trans-2-phenyl-1-bromocyclopentane on reaction with alcoholic KOH produces

(a) 4-phenylcyclopentene
(b) 2-phenylcyclopentene
(c) 1-phenylcyclopentene
(d) 3-phenylcyclopentene

Answer (d) 3-phenylcyclopentene

(9) Increasing order of stability among the three main conformations (i.e. Eclipse, Anti, Gauche) of 2-fluoroethanol is

(a) Eclipse, Gauche, Anti
(b) Gauche, Eclipse, Anti
(c) Eclipse, Anti, Gauche
(d) Anti, Gauche, Eclipse

Answer (c) Eclipse, Anti, Gauche

(10) Following statements regarding the periodic trends of chemical reactivity of the alkali metals and the halogens are given. Which of these statements gives the correct picture?

(a) The reactivity decreases in the alkali metals but increases in the halogens with increase in atomic number down the group
(b) In both the alkali metals and the halogens the chemical reactivity decreases with increase in atomic number down the group
(c) Chemical reactivity increases with increase in atomic number down the group in both the alkali metals and halogens
(d) In alkali metals the reactivity increases but in the halogens it decreases with increase in atomic number down the group

Answer (d) In alkali metals the reactivity increases but in the halogens it decreases with increase in atomic number down the group