Question

When you lower the pH of a solution of sodium benzoate a precipitate forms. (a) What will happen if you raise the pH after the reaction by adding aqueous NaOH? Why?

Answer 1

when you lower the pH value

C6H5COONa(aq) + H+ (aq) ----> C6H5COOH(s) + Na+(aq)

C6H5COOH precipitate forms

When you increase the pH value --->

C6H5COOH (s) + NaOH ---> C6H5COONa(aq) + H2O

If you raise the pH by adding aqueous NaOH, the precipitate will dissociate and a basic solution will form from the reaction of astrong acid and strong base.This will happen because thebenzoic acid will not be able to form in a basic environment including NaOH.With the addition of more reactants, the equilibrium will shift towards the products, creating more sodiumbenzoate and less benzoic acid.