(N/A) For a zero-order reaction $R \rightarrow P$,the rate law is given by: $\text{Rate} = -\frac{d[R]}{dt} = k$. Since the rate is independent of the concentration of the reactant,the plot of $\text{Rate}$ versus $\text{Time}$ is a horizontal line parallel to the $X$-axis,indicating that the rate remains constant over time.
The integrated rate equation for a zero-order reaction is: $[R] = -kt + [R]_0$. This follows the linear equation $y = mx + c$. Therefore,a plot of the concentration of reactant $[R]$ against time $(t)$ yields a straight line with a negative slope.
From this graph:
$1$. The intercept on the $Y$-axis is equal to the initial concentration $[R]_0$.
$2$. The slope of the line is equal to $-k$,where $k$ is the rate constant.