For a reaction,$r = k[A]$. If $50 \%$ of $A$ is decomposed in $120 \ \text{minutes}$,the time taken for $90 \%$ decomposition of $A$ is $............ \ \text{minutes}$.

The decomposition of dinitrogen pentoxide $(N_2O_5)$ follows first order rate law. What will be the rate constant from the given data?
At $t = 800 \ s$,$[N_2O_5] = 1.45 \ mol \ L^{-1}$
At $t = 1600 \ s$,$[N_2O_5] = 0.88 \ mol \ L^{-1}$

For the first order reaction $A \rightarrow B$,the rate constant is $0.25 \ s^{-1}$. If the concentration of $A$ is reduced to half,the value of the rate constant will be: (in $s^{-1}$)

Which of the following is an example of a first-order reaction?

Calculate the time needed for a reactant to decompose $99.9 \%$ if the rate constant of a first-order reaction is $0.576 \ min^{-1}$.

For a first order gas phase reaction:
$A_{(g)} \rightarrow 2 B_{(g)} + C_{(g)}$
Let $P_0$ be the initial pressure of $A$ and $P_t$ be the total pressure at time $t$. The integrated rate equation is: