Chemistry - Ionic Equilibrium Question with Solution | TestHub

Question Explanation:

Identifying the mixture that fails to meet buffer criteria.

Concept:

Neutralization Stoichiometry for Buffer formation.

Solution:

A mixture of a weak acid and a strong base fails to form a buffer if the strong base is in excess or equal to the weak acid, as no weak acid will remain to form the conjugate pair.

Calculation:

1. 4 mmol acid + 2 mmol SB Excess weak acid; Buffer.

2. 2 mmol acid + 4 mmol SB: Excess strong base (2 mmol KOH); Not a buffer.

3. 2 mmol acid + 4 mmol WB Excess weak base; Buffer.

4. 4 mmol acid + 2 mmol WB Excess weak acid; Buffer.

Final Answer: Option B