Chemical Kinetics MCQs for NEET — Chemistry Questions with Answers

In acidic medium the rate of reaction between (BrO₃)^- and Br^- ions is given by the expression

$-\frac{d\left({\mathrm{BrO}}_3^{-}\right)}{dt}=K\left[{\mathrm{BrO}}_3^{-}\right]\left[{\mathrm{Br}}^{-}\right]{\left[{\mathrm{H}}^{+}\right]}^2$

It means:

For a first order reaction A$\to$ Products, the rate of reaction at [A]=0.2 M is 1.0 x10^-2 mol litre^-1 min^-1. The half life period for the reaction is:

The rate of a chemical reaction doubles for every 10°C rise of temperature. If the temperature is raised by 50°C, the rate of the reaction increases by about :

Consider the reaction:

Cl₂(aq) + H₂S(aq) → S(s) +2H⁺(aq) +2Cl^-(aq)

The rate equation for this reaction is rate = k[Cl₂][H₂S] Which of these mechanisms is/are consistent with this rate equation?

A. Cl₂ + H₂S → H⁺ + Cl^- +Cl⁺ + HS^- (slow)

cl⁺ + HS^- → H⁺ +Cl^- + S (fast)

B. H₂S $\iff$ H⁺ + HS^- (fast equilibrium)

Cl₂ + HS^- → 2Cl^- + H⁺ + S (slow)

3A $\to$ C + D, For this reaction it is observed that when initial concentration of A is 10 mole/lit then t_1/2 value of this reaction is 40 min and when initial concentration of A is 20 mole / lit, t_1/2 value has been changed into 20 min. Which of the following is true?

In the following reaction : XA → YB

log[ -d(A)/dt ] = log[-d(B)/dt] +0.3

where -ve sign indicates rate of disappearance the reactant. Then X : Y is

The activation energies of the forward and backward reactions in the case of a chemical reaction are 30.5 and 45.4 KJ/mol respectively. The reaction is

The t_0.5 for the first order reaction.

PCl₅(g) $\to$PCl₃(g) + Cl₂(g) is 20 min. The time in which the conc. of PCl₅ reduces to 25% of the initial conc. is close to 

Consider a reaction A + B + C. If the initial concentration of A was reduced from 4M to 2M in 1 hour and from 2M to 1M in 0.5 hours, the order of the reaction is

A gaseous reaction A₂(g) → B(g) + 1/2C(g) show increase pressure from 100 mm to 120 mm in 5 minutes. The rate of disappearance of (A₂) will be