$\begin{array}{1 1}\text{Concentrated }H_2SO_4\text{ acts as a dehydrating agent}\\\text{Hot concentrated }H_2SO_4\text{ acts as a powerful oxidizing agent}\\\text{The reaction of }PCl_5\text{ with sulphuric acid produces sulphuryl chloride}\\\text{The structure of sulphuric acid in vapour phase is square planar}\end{array} $