Chapter 11: Reactions kinetics
In this article, the author has explained the most important chemistry MCQs from the eleventh chapter( Reactions Kinetics ) of FSC chemistry. All the correct answers have been bold.
1: The activation energy for a simple chemical reaction A –> P is E4 in forward direction. The activation energy for the reverse reaction
a) Can be less than or more than E4
b) Is negative of E4
c) Is always double of E4
d) Is always less than E4
2: Which of the following is correct for the half-life of a substance?
a) Half-life period for N2O5 decomposition is 34 minutes
b) Half-life is independent of initial concentration for all reactions
c) Half-life is dependent on the order of a reaction
d) All of these
3: For a first-order reaction, A –> Products, the concentration of [A] is reduced from 1M to 0.125M in one hour, the t1/2 of this reaction in seconds is
a) 600
b) 300
c) 1200
d) None of these
4: Which of the following is not a characteristic of a catalyst?
a) It cannot affect the equilibrium constant of a reaction
b) It is required in small quantities
c) It takes part in the chemical reaction
d) It does not affect the reaction mechanism
5: 3A —> B + C
It would be a zero-order reaction when
a) The rate of reaction is proportional to the square of the concentration of A
b) The rate remains the same at any concentration of A
c) The rate remains unchanged at any concentration of Band C
d) The rate of reaction doubles if the concentration is increased to double
6: The rate constant of a reaction
a) Is directly proportional to temperature for an exothermic reaction
b) Is directly proportional to temperature for an endothermic reaction
c) Is independent of temperature
d) Is directly proportional to temperature irrespective of the nature of the reaction
7: Among which of the following factor the specific rate constant of a zero-order reaction depends on
a) Temperature
b) Catalyst
c) Pressure
d) Both a and b
9: The rate law for the reaction
RCl + NaOH(aq) —> ROH + NaCl
Is given by rate=k[RCl]. The rate of the reaction will be
a) Doubled on doubling the concentration of sodium hydroxide
b) Halved on reducing the concentration of alkyl halide to one half
c) Decreased on increasing the temperature of the reaction
d) Unaffected by increasing the temperature of the reaction
10: According to the collision theory of reaction rates, an increase of the temperature at which the reaction occurs will in turn increase the rate of the reaction. This caused due to:
a) Greater number of molecules are having the activation energy
b) Greater velocity of reacting molecules
c) Greater number of collisions
d) None of these
11: For an endothermic reaction, where ∆H represents the enthalpy of the reaction in KJ/mole, the minimum value for the energy of activation will be
a) More than ∆H
b) Zero
c) Less than ∆H
d) Equal to ∆H
12: For certain decomposition, the rate is 0.30 m/sec when the concentration of reaction is 0.20 M. Note that reaction is second order, the rate in m/sec when the concentration is increased 3 times, is
a) 0.3
b) 0.9
c) 0.6
d) 2.7
13: A zero-order reaction is one
a) Whose rate is affected by the concentration
b) In which concentration of the reactants do not change with time
c) In which reactants do not react
d) Rate of reaction remains constant