Which of the following combinations would form a buffer solution? a. HF and Lif
b. NH3 and NH4Br
c. HNO2 and NaNO2
d. all of the above
e. none of the above

d . all of the above

Explanation:

A buffer system can be formed in one of two ways:

Which of the following combinations would form a buffer solution?

a. HF and LiF. YES. HF is a weak acid and F⁻ (from LiF) is its conjugate base.

b. NH₃ and NH₄Br. YES. NH₃ is a weak base and NH₄⁺ (from NH₄Br) is its conjugate acid.

c. HNO₂ and NaNO₂. YES. HNO₂ is a weak acid and NO₂⁻ (from NaNO₂) is its conjugate base.

the answer is d. matter from the air combined with the steel wool.