If the concentration is expressed in moles per litre,the unit of the rate constant for a first order reaction is

The half-life period of a $1^{st}$ order reaction is $60 \ minutes$. What percentage will be left over after $240 \ minutes$ (in $\%$)?

For two first-order reactions:
$A \rightarrow \text{Products}$
$B \rightarrow \text{Products}$
If at the same time,$50\% \, B$ has reacted and $94\% \, A$ has reacted,calculate the ratio $K_1/K_2$.

$A$ first order reaction is given as $A \rightarrow \text{products}$. Its integrated rate equation is:

Decomposition of $H_2O_2$ follows a first order reaction. In $50 \ min$,the concentration of $H_2O_2$ decreases from $0.5 \ M$ to $0.125 \ M$. For such decomposition,when the concentration of $H_2O_2$ reaches $0.05 \ M$,the rate of formation of $O_2$ will be:

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 $s^{-1}$)