Which of the following is NOT obtained when a mixture of methyl bromide and ethyl bromide is treated with sodium metal in presence of dry ether?

Calculate the volume of simple cubic unit cell if the radius of particle in it is 400 pm.

Calculate the solubility of a gas having partial pressure 0.15 bar at $25^{\circ} \mathrm{C}$. $\left[\mathrm{K}_{\mathrm{H}}=0.16 \mathrm{~mol} \mathrm{dm}^{-3} \mathrm{bar}^{-1}\right]$

What is the frequency of violet light having wavelength 400 nm ?