- Subject:
Chemistry

- Chapter:
Chemical Kinetics

For a certain reaction a plot of [(c_{0}-c)/c] against time t, yields a straight line. c_{0} and c are concentrations of reactant at t = 0 and t = t respectively. The rate of reaction is:

(a) 3

(b) 0

(c) 1

(d) 2

Hydrogenation of vegetable ghee at 25^{0}C reduces pressure of H_{2} from 2 atom to 1.2 atom in 50 minute. The rate of reaction in terms of molarity per second is:

(a)1.09 x 10^{-6}

(b)1.09 x 10^{-5}

(c)1.09 x 10^{-7}

(d)1.09 x 10^{-8}

A hypothetical reaction, A_{2} +B_{2} $\to $ 2AB mechanism as given below;

A_{2} $\rightleftharpoons $A+ A ............(Fast)

*A+B _{2} → AB + B ............(Slow)*

* A+ *B *→ *AB ............(Fast)

The order of the overall reaction is:

(a) 2

(b) 1

(c) 1.5

(d) zero

Following mechanism has been proposed for a reaction,

*2A+B $\to $D+E*

* A+B$\to $ C+D *...(Slow)

A+ C$\to $ E ...(Fast)

The rate law expression for the reaction is:

(a) r = K[A]^{2}[B]

(b) r=K[A][B]

(c) r= K[A]^{2}

(d) r= K[A][C]

In gaseous reactions important for the understanding of the upper atmosphere H_{2}O and O react bimolecularly to form two OH radicals. $\u2206$H for this reaction is 72kJ at 500 K and E_{a} is 77 kJ mol^{-1}, then E_{a} for the bimolecular recombination of two OH radicals to form H_{2}O and O is:

(a) 3 kJ mol^{-1}

(b) 4 kJ mol^{-1}

(c) 5 kJ mol^{-1}

(d) 7 kJ mol^{-1}

For a reaction *A*$\stackrel{}{\to}$ Product, rate law is $-\frac{d\left[A\right]}{dt}=K[A{]}_{0}$. The concentration of *A* left after time *t* when $t=\frac{1}{K}$ is:

(a) $\frac{[A{]}_{0}}{e}$

(b) $[A{]}_{0}\times e$

(c) $\frac{[A{]}_{0}}{{e}^{2}}$

(d) $\frac{1}{[A{]}_{0}}$

For an exothermic chemical process occurring in two steps as;

(i) A+B$\to $X(Slow)

(ii) X$\to $AB (Fast)

The progress of the reaction can be best described by:

(a)

(b)

(c)

(d) all of these

For the non-stoichiometric reaction 2A + B $\to $ C +D, the following kinetic data were obtained in three separate experiments, all at 298 K.

The rate law for the formation of C is:

(a) d[C]/dt = k[ A][B]

(b) d[C]/dt = k[ A]^{2}[B]

(c) d[C]/dt = k[ A][B]^{2}

(d) d[C]/dt = k[ A]

For the reaction N_{2} + 3H_{2} $\to $ 2NH_{3}, the rate d[NH_{3}]/dt = 2x10^{-4} Ms^{-1} .Therefore, the rate -d[N_{2}]/dt is given as:

(a) 10^{-4} Ms^{-1}

(b) 10^{4} Ms^{-1}

(c) 10^{-2} sM^{-1}

(d) 10^{-4} sM^{-1}

If 'a' is the initial concentration of a substance which reacts according to zero order kinetics and K is rate constant, the time for the reaction to go to completion is:

(a) a/K

(b) 2/Ka

(c) K/a

(d) 2K/a