In a first order reaction,the concentration of the reactant is reduced to $12.5 \%$ in one hour. When was it half completed?

For the first-order reaction $N_2O_5 \to 2NO_2 + \frac{1}{2}O_2$,the half-life at $30 \ ^\circ C$ is $24 \ \text{hours}$. Starting with $10 \ g$ of $N_2O_5$,how many grams of $N_2O_5$ will remain after $96 \ \text{hours}$ (in $g$)?

If compound $A$ reacts with $B$ following first order kinetics with rate constant $2.011 \times 10^{-3} \ s^{-1}$. The time taken by $A$ (in seconds) to reduce from $7 \ g$ to $2 \ g$ will be $.........$ (Nearest Integer) $[\log 5=0.698, \log 7=0.845, \log 2=0.301]$

In a first order reaction,the concentration of the reactant is reduced to $25\%$ in one hour. The half-life period of the reaction is:

Consider a certain reaction $A \rightarrow \text{Products}$ with $k = 2.0 \times 10^{-2} \ s^{-1}$. Calculate the concentration of $A$ remaining after $100 \ s$ if the initial concentration of $A$ is $1.0 \ mol \ L^{-1}$.

Which of the following is a first order reaction?