Question

Sodium salt of acid present in vinegar is an example of :

• A. Salt of strong acid + strong base
• B. Salt of weak acid + strong base
• C. Salt of strong acid + weak base
• D. Salt of weak acid + weak base

Hint:

To find the parent acid and base of any salt:
- Add \(OH^-\) to the cation (e.g., \(Na^+ + OH^- \to NaOH\), a strong base).
- Add \(H^+\) to the anion (e.g., \(CH_3COO^- + H^+ \to CH_3COOH\), a weak acid).
This simple method helps classify any salt.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks us to identify the classification of the salt formed by the neutralization reaction of the acid present in vinegar with a sodium-containing base.

Step 2: Key Formula or Approach:
We must identify the chemical constituents of vinegar and determine the strengths of the acid and base required to synthesize its sodium salt.

Step 3: Detailed Explanation:

• The acid present in vinegar is acetic acid (\(CH_3COOH\)), which is also systematically named as ethanoic acid.

• Acetic acid is a weak organic acid because it only partially dissociates into ions when dissolved in water:
\[ CH_3COOH\text{(aq)} \rightleftharpoons CH_3COO^-\text{(aq)} + H^+\text{(aq)} \]

• The sodium salt of this acid is sodium acetate (\(CH_3COONa\)).

• Sodium acetate is chemically prepared by reacting acetic acid (a weak acid) with sodium hydroxide (\(NaOH\)), which is a strong, highly soluble mineral base:
\[ CH_3COOH\text{(aq)} + NaOH\text{(aq)} \to CH_3COONa\text{(aq)} + H_2O\text{(l)} \]

• Since this salt is synthesized from a weak acid (\(CH_3COOH\)) and a strong base (\(NaOH\)), it is classified as a "salt of a weak acid and a strong base."

• Due to the dominance of the strong base conjugate, an aqueous solution of sodium acetate undergoes anionic hydrolysis to yield a basic solution with a pH value greater than 7:
\[ CH_3COO^-\text{(aq)} + H_2O\text{(l)} \rightleftharpoons CH_3COOH\text{(aq)} + OH^-\text{(aq)} \]

Step 4: Final Answer:
The sodium salt of the acid in vinegar is an example of a salt of a weak acid + strong base.