Question

Select any of the following combinations which would make a good buffer solution?

Answer 1

Answer:

b. 0.05 M H₂CO₃ + 0.05 M KHCO₃

d. 0.1M HCN + 0.2M NaCN

g. 0.2M NH₃ + 0.1M NH₄Br

Explanation:

A buffer solution consists of the following components:

• A weak acid and its conjugate base.
• A weak base and its conjugate acid.

Which would make a good buffer solution?

a. 0.3 M HC₂H₃0₂ + 0.1 M HCI

It does not have the components of a buffer solution. HCl is a strong acid.

b. 0.05 M H₂CO₃ + 0.05 M KHCO₃

It is a good buffer because it has a weak acid (H₂CO₃) and its conjugate base (HCO₃⁻), which comes from the salt.

c. 0.05 M KC₂H₃O₂

It does not have the components of a buffer solution.

d. 0.1M HCN + 0.2M NaCN

It is a good buffer because it has a weak acid (HCN) and its conjugate base (CN⁻), which comes from the salt.

e. 0.2M NaF + 0.2M NaOH

It does not have the components of a buffer solution. NaOH is a strong base.

f. 0.3M NH₄Cl

It does not have the components of a buffer solution.

g. 0.2M NH₃ + 0.1M NH₄Br

It is a good buffer because it has a weak base (NH₃) and its conjugate acid (NH₄⁺), which comes from the salt.