Consider the reaction,
$3\text{I}^-_{(aq)} + \text{S}_2\text{O}_8^{2-}{}_{(aq)} \longrightarrow \text{I}_3^-{}_{(aq)} + 2\text{SO}_4^{2-}{}_{(aq)}$
If the rate of formation of $\text{SO}_4^{2-}$ at a particular time is $2.2 \times 10^{-2}\,\text{mol dm}^{-3}\,\text{s}^{-1}$. Calculate the rate of consumption of $\text{I}^-$.

For a first order reaction, half life is $5$ hour. What time is required to reduce $10$ g of reactant to $2.5$ g ?

Which of following forces is responsible for physisorption ?

Which of the following ranges of particle size defines nano scale ?