Question

A buffer solution is made up of HNO₂ and NO₂ - a strong acid, such as HCl, was added to the buffer. Which buffer component will react with the added HCl to neutralize the added acid?

1) HNO₂
2) NO₂ -

Answer 1

NO₂⁻, the conjugate base of the weak acid HNO₂, will react with the H+ ions from a strong acid like HCl in a buffer solution to neutralize the acid and maintain pH stability.

Step-by-step explanation:

When a strong acid like HCl is added to a buffer solution made up of HNO₂ and NO₂⁻, the NO₂⁻, which is the salt's anion, will react with the added H+ ions to neutralize the added acid. This occurs because in a buffer system, the weak acid (HNO₂) and its conjugate base (NO₂⁻) work together to resist changes in pH. The added H+ ions from HCl will combine with the NO₂⁻ ions to form more HNO₂, thus keeping the pH relatively stable.