For any reaction,if we plot a graph between time $t$ and $\log (a - x)$,a straight line is obtained. The order of reaction is

$A$ first order reaction is $75 \%$ completed in $60 \ min$. The time required for its $50 \%$ completion is: (in $min$)

For the decomposition of $N_2O_5$ according to the equation $2N_2O_5(g) \to 4NO_2(g) + O_2(g)$,the reaction is of first order. After $30 \, \min$ from the start of the reaction in a closed vessel,the total pressure is $305.5 \, mm \, Hg$,and at the end of complete decomposition,the total pressure is $587.5 \, mm \, Hg$. Calculate the rate constant of the reaction.

Hydrolysis of $DDT$ is a first order reaction,its half-life is $10 \ years$. Time required to hydrolyse $10 \ g$ of $DDT$ to half is ......... $years$.

$A$ $20 \%$ first-order reaction is completed in $32 \ \text{min}$. How much time (in $\text{min}$) will it take for $60 \%$ of the reaction to be completed (in $.00$)?

For a first-order gas-phase reaction $A(g) \to B(g) + C(g)$, let $p_i$ be the initial pressure of gas $A$ and $p_t$ be the total pressure of the reaction mixture at time $t$. The expression for the rate constant $(k)$ is: