JAMB Chemistry 2011 Paper

Concept:A non-volatile acid displaces a more volatile acid from its salt.Explanation:Concentrated tetraoxosulphate(VI) acid, $\mathrm{H}_2\mathrm{SO}_4$, has a high boiling point of about $388^\circ\mathrm{C}$.Because of this, it is non-volatile and does not escape as vapour easily.When it reacts with a nitrate salt such as $\mathrm{NaNO}_3$, it displaces the more volatile $\mathrm{HNO}_3$ from the salt.The $\mathrm{HNO}_3$ vapour is then collected by cooling.This high boiling point is the property that makes $\mathrm{H}_2\mathrm{SO}_4$ suitable for preparing $\mathrm{HNO}_3$.Answer:A. boiling point