Which among following is a strongest base?

What is the vapour pressure of a solution containing 0.1 mol of non volatile solute dissolved in 16.2 g water? $\left(\mathrm{P}_1^0=24 \mathrm{mmHg}\right.$, molar mass of water $18 \mathrm{~g} \mathrm{~mol}^{-1}$ )

Which of the following compounds does not undergo Williamson's synthesis?

Find the constant external pressure required to expand a gas from 2.5 L to 4.5 L if amount of work done is 500 J at 298 K ?