For a first order reaction,to obtain a positive slope,we need to plot $...$ where $[A]$ is the concentration of reactant $A$.

Dissociation of $N_2O_5$ dissolved in $CCl_4$ at constant temperature: $N_2O_{5(soln)} \to 2NO_{2(soln)} + \frac{1}{2}O_{2(g)}$. This is a first order reaction. The velocity constant is $5.0 \times 10^{-4} \ s^{-1}$. The initial concentration of $N_2O_5$ is $0.25 \ mol \ L^{-1}$. How much time is required to produce $0.20 \ mol \ L^{-1}$ concentration of $NO_2$ (in $s$)?

The time taken for $10 \%$ completion of a first order reaction is $20 \ min$. Then,for $19 \%$ completion,the reaction will take (in $min$)

The reaction $X \rightarrow$ products is a first-order reaction. If the concentration of reactant $X$ decreases from $0.1 \, M$ to $0.025 \, M$ in $40 \, \text{minutes}$,what will be the rate of the reaction when the concentration of the reactant is $0.01 \, M$?

For a first order reaction,a plot of $\log(a-x)$ against time is a straight line with negative slope equal to

$R \rightarrow P$ is a first order reaction. For this reaction,a graph of $\ln [R]$ (on $y$-axis) and time (on $x$-axis) gives a straight line with a negative slope. The intercept on the $y$-axis is equal to ($k =$ rate constant):