JEE Chemistry Equilibrium MCQs Set A

Question. Which of the following is not a general characteristic of equilibria involving physical processes ?
(a) All the physical processes stop at equilibrium
(b) The opposing processes occur at the same rate and there is dynamic but stable condition
(c) All measurable properties of the system remain constant
(d) Equilibrium is possible only in a closed system at a given temperature

Answer: A

Question.  The liquid which has a ………..vapour pressure is more volatile and has a ………….boiling point
(a) Higher, lower
(b) Higher , higher
(c) Lower, lower
(d) Lower, higher

Answer: A

Question. Boiling point of the liquid depends on the atmospheric pressure. It depends on the altitude of the place; at high altitude the boiling point
(a) decreases
(b) either decreases or increases
(c) remains same
(d) increases

Answer: A

Question. In an experiment three watch glasses containing separately 1mL each of acetone, ethyl alcohol, and water are exposed to atmosphere and the experiment with different volumes of the liquids in a warmer room is repeated, it is observed that in all such cases the  liquid eventually disappears and the time taken for complete evaporation in each case was different. The possible reason is/are
(a)   All of the above
(b) the temperature is different
(c) the amount of the liquids is different
(d) the nature of the liquids is different

Answer: A

Question. A small amount of acetone is taken in a watch glass and it is kept open in atmosphere. Which statement is correct for the given experiment?
(a) The rate of condensation from vapour to liquid state is much less than the rate of evaporation
(b) The rate of condensation from vapour to liquid state is equal or less than the rate of evaporation
(c) The rate of condensation from vapour to liquid state is equal to the rate of evaporation
(d) The rate of condensation from vapour to liquid state is higher than the rate of evaporation

Answer: A

Question. A reaction is said to be in equilibrium when
(a) the rate of transformation of reactant to products is equal to the rate of transformation of products to the reactants.
(b) 50% of the reactants are converted to products
(c) None of these
(d) the volume of reactants is just equal to the volume of the products

Answer: A

Question. Which of the following is not true about a reversible reaction?
(a) Number of moles of reactants and products is always equal
(b) It can be attained only in a closed container
(c) It cannot be influenced by a catalyst
(d) The reaction does not proceed to completion

Answer: A

Question. If the synthesis of ammonia from Haber's process is carried out with exactly the same starting conditions (of partial pressure and temperature) but using D₂ (deuterium) in place of H₂. Then
(a) the composition of reaction mixture will remain same at equilibrium.
(b) Use of isotope in reaction will not produce ammonia
(c) At equilibrium rate of forward reaction will be greater than the rate of reverse reaction
(d) the equilibrium will be disturbed

Answer: A

Question. What are the product formed when Deuterium is added equilibrium reaction of H₂ and I₂ ?
(i) HD    (ii) DI
(iii) D₂   (iv) HI
(a) All of these
(b) (i) and (ii)
(c) (i), (ii) and (iv)
(d) (ii) and (iv)

Answer: A

Question. If a system is at equilibrium, the rate of forward to the reverse reaction is
(a) equal
(b) at equilibrium
(c) less
(d) high

Answer: A

Question. In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled then the equilibrium constant will
(a) Remain the same
(b) Be halved
(c) Also be doubled
(d) Become one-fourth

Answer: A

Question. On doubling P and V with constant temperature the equilibrium constant will
(a) remain constant
(b) become one-fourth
(c) become double
(d) None of these

Answer: A

Question.  If K_c is in the range of ______ appreciable concentrations of both reactants and products are present
(a) 10 ^{– 3} to 10³
(b) 10 ^{– 5} to 10³
(c) 10⁺³ to 10 ^{– 3}
(d) 10^–4 to 10⁴

Answer: A

Question. The reaction quotient Q is used to
(a) predict the direction of the reaction
(b) calculate equilibrium concentrations
(c) calculate equilibrium constant
(d) predict the extent of a reaction on the basis of its magnitude

Answer: A