Answer:
0.99%
Step-by-step explanation:
The Henderson-Hasselbalch equation relates the ratio of the ionized to the non-ionized form of an acid as follows:
pH = pKa + log([A⁻]/[HA])
Inserting the values for pH and pKa and solving gives:
7.4 = 5.2 + log([A⁻]/[HA])
2 = log([A⁻]/[HA])
[A⁻]/[HA] = 100/1
The percentage of the weak acid in non-ionized form (HA) is then calculated:
[HA]/([A⁻] + [HA]) = 1/(100+1) x 100% = 0.99&