Question

A 1 liter solution contains 0.304 M acetic acid and 0.228 M sodium acetate. Addition of 0.114 moles of perchloric acid will:_______ (Assume that the volume does not change upon the addition of perchloric acid.)

Raise the pH slightly
Lower the pH slightly
Raise the pH by several units
Lower the pH by several units
Not change the pH
Exceed the buffer capacity

Answer 1

Lower the pH slightly

Step-by-step explanation:

A buffer is defined as the mixture between weak acid and conjugate base. In the problem, acetic acid is the weak acid and sodium acetate the conjugate base.

When a strong acid as perchloric acid is added to a buffer, the pH decreases slightly because the acid reacts with conjugate base producing weak acid and not affecting directly the concentration of H⁺ ions.