A diprotic acid H₂A has pK_a1 = 3.0 and pK_a2 = 8.0
CHEMISTRY · Single correct · A Level · Chemistry · Acids and bases · Acids and bases
Problem
A diprotic acid H₂A has pK_a1 = 3.0 and pK_a2 = 8.0. It is titrated with 0.100 M NaOH at 25 °C.
Which pair of indicators is most appropriate for detecting the first and second equivalence points, respectively?
(a) Bromothymol blue for the first and thymolphthalein for the second equivalence point
(b) Methyl red for the first and phenolphthalein for the second equivalence point
(c) Phenolphthalein for the first and alizarin yellow R for the second equivalence point
(d) Methyl orange for the first and bromothymol blue for the second equivalence point