Question

Which of the following does not form a buffer solution?

• A. NH3+HCL (2:1 mole ratio)
• B. CH3CO2H + NaOH (2:1 mole ratio)
• C. NaOH + CH3COOH (1:1 mole ratio)
• D. NH4Cl + NH3 (1:1 mole ratio)

Answer 1

Answer: (C)

NaOH + CH3COOH (1:1 mole ratio)

Answer 2

The correct option is: (C): NaOH + CH3COOH (1:1 mole ratio).

The solution of NaOH (sodium hydroxide) and CH3COOH (acetic acid) in a 1:1 mole ratio does not form a buffer solution. A buffer solution consists of a weak acid and its conjugate base, or a weak base and its conjugate acid. This combination helps the solution resist changes in pH when an acid or base is added.

In the case of NaOH and CH3COOH, you have a strong base (NaOH) and a weak acid (CH3COOH), but they are not a conjugate acid-base pair. Buffer solutions require a weak acid and its conjugate base (or vice versa) to effectively maintain a stable pH. The weak acid in the buffer system donates protons (H+) to counteract any added base, while its conjugate base absorbs protons to counteract any added acid.