For a chemical reaction $\mathrm{A} \rightarrow \mathrm{B}$, it was found that concentration of B is increased by $0.2 \mathrm{~mol} \mathrm{~L}^{-1}$ in 30 min . The average rate of the reaction is $\_\_\_\_$ $\times 10^{-1} \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~h}^{-1}$. (in nearest integer)