Question

question
in a buffer solution made of acetic acid and sodium acetate, if a small amount of acid is added, the added acid will react with which of the following?
select the correct answer below;
hydronium ions
sodium ions
acetic acid
acetate ions

Explanation:

Step1: Understand buffer solution

A buffer solution consists of a weak acid (acetic acid, \(CH_3COOH\)) and its conjugate base (acetate ions, \(CH_3COO^-\)).

Step2: Analyze reaction with added acid

When a small amount of acid (e.g., \(H^+\)) is added, the acetate ions (\(CH_3COO^-\)) will react with the \(H^+\) ions. The reaction is \(CH_3COO^-+H^+
ightleftharpoons CH_3COOH\). Hydronium ions (\(H_3O^+\)) are not what the added acid reacts with (added acid is a source of \(H^+\)). Sodium ions (\(Na^+\)) are spectator ions and do not participate in the reaction. Acetic acid (\(CH_3COOH\)) is the weak acid in the buffer and does not react with the added \(H^+\) in the way to neutralize the effect of added acid (the conjugate base does that). So the added acid reacts with acetate ions.

Answer:

D. acetate ions