Question

A buffer solution that is (0.462 M) in HF and (0.462 M) in NaF has a pH of (3.14). Addition of which of the following would increase the capacity of the buffer for added (OH⁻)?

a) NaCl

b) HCl

c) NaOH

d) HF

Answer 1

To increase the buffer's capacity for added OH-, the correct choice is to add more of the acid component, HF, thus option (d) HF is the correct answer.

Step-by-step explanation:

The addition of either NaCl or NaOH won't significantly affect the buffer's ability to neutralize added OH- ions, as NaCl will not react with the buffer components, and NaOH will only deplete the buffer's acid component (HF). However, adding more of the buffer's acid component, HF, would increase its capacity to deal with added OH-.

This is because while NaOH would react with the acid (HF) in the buffer, depleting its ability to neutralize additional OH-, adding more HF would provide additional acid to react with OH- ions.

Thus, the correct answer to the question is (d) HF, as it will increase the buffer capacity for added OH- by providing more acid to neutralize additional basic substances.