Chemistry - Chemical Kinetics Question with Solution | TestHub

From the given graph, the plot of concentration $[R]$ versus time $t$ is a straight line with a negative slope.

The equation for this straight line can be written as:
$y=mx+c$
$[R]=(\text{slope})\times t+\text{intercept}$

Given that the intercept is $[R_0]$ and the slope is $-k$, the equation becomes:
$[R]=-kt+[R_0]$

This equation represents the integrated rate law for a zero-order reaction. For a zero-order reaction, the rate of reaction is independent of the concentration of the reactant:
$\text{Rate}=-\frac{d[R]}{dt}=k[R{]}^0=k$

Integrating both sides:
${\int }_{[R_0]}^{[R]}d[R]=-k{\int }_0^{t}dt$
$[R]-[R_0]=-kt$
$[R]=-kt+[R_0]$

Since the graph matches this equation, the order of the reaction is $0$.

Answer: $0$