Which one of the following combinations cannot function as a buffer solution?

a.) HCN & KCN

b.) NH3 & (NH4) 2SO4

c.) HNO3 & NANO3

d.) HF & NaF

e.) HNO2 & NaNO2

c.) HNO₃ & NaNO₃

Explanation:

A buffer system has 2 components:

A weak acid and its conjugate base or A weak base and its conjugate acid

Which one of the following combinations cannot function as a buffer solution?

a.) HCN & KCN. YES. HCN is a weak acid and CN⁻ (coming from KCN) its conjugate base.

b.) NH₃ & (NH₄) ₂SO₄. YES. NH₃ is a weak base and NH₄⁺ (coming from (NH₄) ₂SO₄) its conjugate acid.

c.) HNO₃ & NaNO₃. NO. HNO₃ is a strong acid.

d.) HF & NaF. YES. HF is a weak acid and F⁻ (coming from NaF) its conjugate base.

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