For the first order reaction A → 2 B, 1 mole of reactant A gives 0.2 moles of B after 100 minutes. The half life of the reaction is \ \ \ \ min.…

For the first order reaction $\displaystyle \mathrm{A} \rightarrow 2 \mathrm{~B}, 1$ mole of reactant A gives $\displaystyle 0.2$ moles of B after $\displaystyle 100$ minutes. The half life of the reaction is \_\_\_\_ min. (Round off to the Nearest Integer). [Use : $\displaystyle \ln 2=0.69, \ln 10=2.3$ Properties of logarithms : $\displaystyle \ln x^y=y \ln x$; $$\left.\ln \left(\frac{x}{y}\right)=\ln x-\ln y\right] $$