Which of the following is correct regarding $t_{1/2}$ of a reaction if we double the initial concentration of a reactant in a first-order reaction?

The reaction $2N_2O_5 \,(g) \to 4NO_2 \,(g) + O_2 \,(g)$ follows first order kinetics. The pressure of a vessel containing only $N_2O_5$ was found to increase from $50 \, mmHg$ to $87.5 \, mmHg$ in $30 \, min$. The pressure exerted by the gases after $60 \, min$ will be .......... $mmHg$ (assume temperature remains constant).

The half-life period of a first order reaction is $15 \ minutes$. The amount of substance left after one hour will be

$A$ first order reaction is $50 \%$ complete in $16 \ min$. How much time is required to complete $87.5 \%$ of the reaction (in $min$)?

For a first-order reaction,the time taken for the concentration of the reactant to reach $3/4$ of its initial value is $t_{1/4}$. If the rate constant for the reaction is $K$,then $t_{1/4}$ can be expressed as: (in $/K$)

$A$ first order reaction requires $30 \ min$ for $50\%$ completion. The time required to complete the reaction by $75\%$ will be .......... $\min.$