Which of the following element in +1 oxidation state has largest ionic radius?

Identify the product in following reaction. Pent -3-enenitrile $\xrightarrow[\mathrm{H}_3 \mathrm{O}^{+}]{\mathrm{AlH}(\mathrm{B}-\mathrm{B})_2}$ product

Which of the following molecules has zero dipole moment?

What is the concentration of an electrolyte solution to have molar conductivity of $101 \Omega^{-1} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$ and conductivity of $1.01 \times 10^{-2} \Omega^{-1} \mathrm{~cm}^{-1}$ at $298 \mathrm{~K} ?$