$A$ first order reaction is $25 \%$ completed in $40 \ min$. What is the rate constant $k$ for the reaction?

The rate constant of a reaction is $k = 3.28 \times 10^{-4} \text{ s}^{-1}$. Find the order of the reaction.

Half-life for a first order reaction is $6.93 \ hour$. What is the time required for $80 \%$ completion of the reaction (in $hours$)?

The decomposition of substance $A$ in a solution follows first-order kinetics. Vessel-$I$ contains $1 \ L$ of $1 \ M$ solution of $A$. Vessel-$II$ contains $100 \ mL$ of $0.6 \ M$ solution of $A$. If the concentration of $A$ in Vessel-$I$ becomes $0.25 \ M$ in $8 \ hr$,then the time required for the concentration of $A$ in Vessel-$II$ to become $0.3 \ M$ is ......... $hr$.

In the equation $Kt = \ln C_0 - \ln C_t$,the graph between $t$ and $\ln C_t$ is a .....

$N_2O_{(g)} \to N_{2(g)} + \frac{1}{2}O_{2(g)}$
In a closed vessel,the reaction follows first-order kinetics. If starting with pure $N_2O_{(g)}$,the total pressure after time $t$ is $P_t$ and after a very long time is $P_{\infty}$,then which of the following expressions is correct?