Question

Match the rate law given in column I with the dimensions of rate constant given in column II and mark the appropriate choice.

Column I	Column II
(A) $Rate=k[N{H}_3{]}^0$	(i) $mol{L}^{-1}{s}^{-1}$
(B) $Rate=k\left[H_2{O}_2\right]\left[I^{-}\right]$	(ii) $Lmo{l}^{-1}{s}^{-1}$
(C) $Rate=k[C{H}_{3}CHO{]}^{3/2}$	(iii) $s^{-1}$
(D) $Rate=k\left[C_2{H}_{5}Cl\right]$	(iv) $L^{1/2}mo{l}^{-1/2}{s}^{-1}$

• A. $\left(A\right)\to \left(iv\right),\left(B\right)\to \left(iii\right),\left(C\right)\to \left(ii\right),\left(D\right)\to \left(i\right)$
• B. $\left(A\right)\to \left(i\right),\left(B\right)\to \left(ii\right),\left(C\right)\to \left(iii\right),\left(D\right)\to \left(iv\right)$
• C. $\left(A\right)\to \left(ii\right),\left(B\right)\to \left(i\right),\left(C\right)\to \left(iv\right),\left(D\right)\to \left(iii\right)$
• D. $\left(A\right)\to \left(i\right),\left(B\right)\to \left(ii\right),\left(C\right)\to \left(iv\right),\left(D\right)\to \left(iii\right)$

Answer 1

The correct option is D $\left(A\right)\to \left(i\right),\left(B\right)\to \left(ii\right),\left(C\right)\to \left(iv\right),\left(D\right)\to \left(iii\right)$

(A) $Rate=k[N{H}_3{]}^0$

It is zero order reaction.

$\therefore$ Units of rate constant are same as rate.

i.e $mol{l}^{-1}{s}^{-1}$

(B) $Rate=k\left[H_2{O}_2{]}^1\right[I^{-}{]}^1$

It is second order reaction as order $=1+1=2$

$\therefore$ Units of Rate constant are $Lmo{l}^{-1}{s}^{-1}$

(C) $Rate=k[C{H}_{3}CHO{]}^{3/2}$

It is fractional order reaction with order $=\frac{3}{2}$

$\therefore$ Units of rate constant are $L^{\frac{1}{2}}mo{l}^{-\frac{1}{2}}{s}^{-1}$

(D) $Rate=k[C_2{H}_{5}Cl{]}^{-1}$

It is first order reaction. So units of rate constant are $s^{-1}$