Question

Which of the following gives a buffer solution when equal volumes of the two solutions are mixed?a. 0.20 MHF and 0.10 MNaOH.b. 0.10 MHF and 0.10 MNaOH.c. 0.10 MHF and 0.10 MNaF.d. 0.10 MHCl and 0.20 MNaF.

Answer 1

Answer:

a. 0.20 M HF and 0.10 M NaOH.

c. 0.10 M HF and 0.10 M NaF

d. 0.10 M HCl and 0.20 M NaF.

Explanation:

A buffer solution consists of a weak acid and its conjugate base, or of a weak base and its conjugate acid.

In this case, HF is the weak acid and F⁻ is its conjugate base.

Let's go case-by-case:

a. 0.20 M HF and 0.10 M NaOH.

• Some -but not all- HF will react and produce F⁻, leaving a buffer solution.

b. 0.10 M HF and 0.10 M NaOH.

• All HF will react, not a buffer solution.

c. 0.10 M HF and 0.10 M NaF.

• There's no reaction, and both HF and F⁻ are directly added, it is a buffer solution.

d. 0.10 M HCl and 0.20 M NaF.

• Some F⁻ will react and produce HF, leaving a buffer solution.

The correct answers are A), C) and D).