For equal volumes of \({\text{1.0 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}\) solutions of hydrochloric acid, HCl(aq), and methanoic acid, HCOOH(aq), which statements are correct?

I.     HCl dissociates more than HCOOH

II.     HCl is a better electrical conductor than HCOOH

III.     HCl will neutralize more NaOH than HCOOH

A.     I and II only

B.     I and III only

C.     II and III only

D.     I, II and III

A

With a difficulty index of 24%, this was the second most challenging question on the paper and the responses seem to indicate that the vast majority of candidates think that a strong acid requires more moles of alkali for neutralization than a weak acid. Surprisingly the question proved quite a weak discriminator, with a discrimination index of only 0.15.