WAEC Chemistry 2011 Paper

Concept:Conductivity depends on the total number and charge of ions produced per formula unit in solution.Explanation:All the solutions have the same molar concentration, so compare how many ions each solute produces when dissolved in water.$\mathrm{CH_3COOH}$ is a weak acid, so it ionises only slightly and gives few ions.$\mathrm{H_2CO_3}$ is also a weak acid, so it also produces very few ions in solution.$\mathrm{H_2SO_4}$ is a strong acid and fully ionises to give $\mathrm{2H^+ + SO_4^{2-}}$, producing three ions per formula unit.$\mathrm{NaOH}$ is a strong base, but it produces only $\mathrm{Na^+ + OH^-}$, which is two ions per formula unit.Since $\mathrm{H_2SO_4}$ gives the highest number of ions in equimolar solutions, it has the highest conductivity.Answer:C. $\mathrm{H_2SO_4(aq)}$