The rate constant of a first order reaction is $1.15 \times 10^{-3} \mathrm{~s}^{-1}$. How long will 5 g of reactant take to reduce to 3 g ?

Which of the following is an example of first order reaction?

For a reaction,

$\mathrm{A}+\mathrm{B} \longrightarrow$ product, it is found that rate law is $\mathrm{r}=\mathrm{k}[\mathrm{A}]^{1.5}[\mathrm{~B}]^{2.5}$. What is the order of reaction?

The half life values for two different first order reaction A and B are 75 minute and 2.5 hour respectively. What is the $\frac{r_B}{r_A}$ ratio of rate constants?