A container contains equal masses of $\mathrm{H}_2, \mathrm{He}$, $\mathrm{CO}_2$ and Ne at a certain temperature. Which of the following gas exerts maximum partial pressure?

The reaction of aryl halide with sodium metal in dry ether to give biphenyl is known as

Identify the final product obtained when ${ }^a$ mixture of vapours of phenol and hydrogen is passed over nickel catalyst at 433 K .

What is the numerical value of angular momentum for an electron in first orbit of hydrogen atom? ( $\mathrm{h}=6.626 \times 10^{-34} \mathrm{Js}$ )