What happens to the solution if sodium acetate is added to a solution of acetic acid?

The pH of the solution increases.

Explanation:

Acetic acid is a weak acid, this means it does not dissociate completely in aqueous solution.

Sodium acetate on the other hand is a salt which dissociates to give acetate ions ad sodium ion.

Also, sodium acetate is the conjugate base of acetic acid. A mixture of a weak acid and its conjugate base is a buffer solution.

The mixture leads to a greater concentration of acetate ion, CH3COO-. shere is an increase in the pH of the solution.

So, when you are adding sodium acetate to a solution of acetic acid, concentration of acetate anions increases. Thus, there will be a decrease of hydronium ions resulting in pH increase.