If the rate constant for a first order reaction is $2.303 \times 10^{-3} \ s^{-1}$,find the time required to reduce $4 \ g$ of the reactant to $0.2 \ g$. (in $hours$)

The first order rate constant for the decomposition of $N_2O_5$ is $6.2 \times 10^{-4} \ s^{-1}$. The half-life period for this decomposition in seconds is:

$10 \ g$ mixture of two gases $A_2$ (mol. wt. $= 20$) and $B_2$ (mol. wt. $= 30$),which decompose by first order kinetics,was taken in a vessel. The half-life of decomposition of $A_2$ and $B_2$ are $2 \ hours$ and $3 \ hours$ respectively. After $6 \ hours$,the weight of the mixture of $A_2$ and $B_2$ is found to be $2 \ g$. Find the weight of $A_2$ in the initial mixture in $g$.

$T_{50}$ of a first-order reaction is $10 \ min$. Starting with $10 \ mol \ L^{-1}$,the rate after $20 \ min$ is:

$A$ first order reaction is half completed in $45 \, \text{minutes}$. How long does it need for $99.9 \%$ of the reaction to be completed? (in $hr$)

For a first order reaction,the ratio between the time taken to complete $\frac{3}{4}$ th of the reaction and time taken to complete half of the reaction is