What is rate constant of a first order reaction if $60 \%$ reactant decompose in 45 minute?

What is the product obtained when benzonitrile is treated with $\mathrm{C}_6 \mathrm{H}_5 \mathrm{MgBr}$ in dry ether and then hydrolyzed?

Which of the following compounds is amphoteric in nature?

What is the energy associated with first orbit of $\mathrm{He}^{+}$?