If $75 \%$ of a first order reaction was completed in $90 \ minutes$,$60 \%$ of the same reaction would be completed in approximately (in minutes)..........
(Take: $\log 2=0.30 ; \log 2.5=0.40)$

$A$ flask is filled with equal moles of $A$ and $B$. The half-lives of $A$ and $B$ are $100 \, s$ and $50 \, s$ respectively and are independent of the initial concentration. The time required for the concentration of $A$ to be four times that of $B$ is $.... \, s.$
(Given : $\ln 2 = 0.693$ )

How much time is required for a first-order reaction to be $3/4$ complete?

If the concentration of a first order reaction is increased by $x$ times,then the rate constant $(k)$ becomes

For the first-order reaction $N_2O_5 \text{ (in } CCl_4) \rightarrow 2NO_2 + \frac{1}{2}O_{2(g)}$,the rate constant is $6.2 \times 10^{-4} \, s^{-1}$. What will be the rate of reaction when $[N_2O_5] = 1.25 \, mol \, L^{-1}$?

The following data were obtained during the first order thermal decomposition of a gas $A$ at constant volume:
$A_{(g)} \rightarrow 2 B_{(g)} + C_{(g)}$

$S.No.$	$Time/s$	$Total Pressure/(atm)$
$1.$	$0$	$0.1$
$2.$	$115$	$0.28$

The rate constant of the reaction is . . . . . . $\times 10^{-2} \ s^{-1}$ (nearest integer).