Which of the following is correct with respect to the graph given? $\begin{aligned} & {[R]=\text {…
Which of the following is correct with respect to the graph given?
$\begin{aligned} & {[R]=\text { Concentration at time ' } t \text { ' }} \\ & {[R]_0=\text { Initial concentration }}\end{aligned}$
I, III represent first order and II represents zero order reaction
I, II represent zero order and III represents first order reaction
I, II, III all represent zero order reactions
I, II, III all represent first order reaction
Solution
For a zero order reaction :-
Rate $=\mathrm{K}[\mathrm{A}]^0=\mathrm{K}$
Thus, the rate does not change with concentration. Therefore, I is of zero order reaction. For the integrated rate law of zero order :-
$\mathrm{C}=-\mathrm{kt}+\mathrm{C}_0$
Thus, the graph II is for a zero order reaction.
For a first order reaction:-
$\mathrm{t}=\frac{2.303}{\mathrm{~K}} \log \frac{[\mathrm{R}]_0}{[\mathrm{R}]}$ or $\log \frac{[\mathrm{R}]_0}{[\mathrm{R}]}=\frac{\dot{\mathrm{K}}}{2.303} \mathrm{t}$
Thus, III is a graph for a first order reaction.
