Which statement best explains why a buffer solution loses its ability to resist pH…
CHEMISTRY · Single correct · A Level · Chemistry · Acids and bases · Acids and bases
Problem
Which statement best explains why a buffer solution loses its ability to resist pH change after a large quantity of strong acid has been added?
(a) The strong acid lowers the solution pH far below the buffer’s pKa, so the Henderson–Hasselbalch relationship no longer applies and the buffer stops working.
(b) The conjugate base component of the buffer has been almost completely converted to its conjugate acid, so additional H+ ions can no longer be neutralized.
(c) Strong acids are completely ionized and therefore cannot be neutralized by a weak conjugate base, leaving the added H+ in solution and causing a large pH drop.
(d) Adding a large volume of acid dilutes both members of the buffer pair to such low concentrations that they are unable to consume any more H+.