Titration: Strong base and strong acid

Question

Consider a titration of 0.0200 moles HCl (a strong acid) with NaOH (a strong base). At the equivalence point, the total volume of the solution is 78.9 mL. What is the pH of this solution at this equivalence point?

Answer 1

When a strong acid and strong base interact, the pH at the equivalence point should be 7 (neutral). This can be seen as follows:

HCl + NaOH ==> NaCl + H2O

At equivalence point, moles HCl = mols NaOH so complete neutralization has occurred. This produces NaCl and water, both of which should have a neutral pH of 7.

As an aside, when a strong acid is titrated with a weak base, the pH at the equivalence point will be <7.

When a weak acid is titrated with a strong base, the pH at the equivalence point will be >7.