Question 10.10: Write an equation for each of the following buffering action......
Write an equation for each of the following buffering actions.
a. The response of H_{2}PO_{4} ^{-}/HPO_{4} ^{2-} buffer to the addition of H_{3}O^{+} ions
b. The response of HCN/CN^{-} buffer to the addition of OH^{-} ions
a. The base in a conjugate acid–base pair is the species that responds to the addition of acid. (Recall, from Section 10.2, that the base in a conjugate acid–base pair always has one less hydrogen than the acid.) The base for this reaction is HPO_{4} ^{2-}. The equation for the buffering action is
H_{3}O^{+} + HPO_{4} ^{2-} → H_{2}PO_{4} ^{-} + H_{2}O
In the buffering response, the base is always converted into its conjugate acid.
b. The acid in a conjugate acid–base pair is the species that responds to the addition of base. The acid for this reaction is HCN. The equation for the buffering action is
HCN + OH^{-} → CN^{-} + H_{2}O
Water will always be one of the products of buffering action.