A student adds 10 mL of hydrochloric acid to a 20 ml sodium hydroxide solution. What will most likely happen to the pH of the solution?

Answer: The pH decreases

Explanation:

- Hydrochloric acid, as an acid has a pH value below 7

- Sodium hydroxide, as an alkali has a pH value above 7.

The alkali neutralizes the acid to give a salt as in the equation:

HCl (aq) + NaOH (aq) - -> NaCl (aq) + H2O (l)

Hence, the aqeous sodium chloride, NaCl has a pH value of 7 (neutral) which is then a decrease from the above 7 pH value of the sodium hydroxide solution.

Thus, the pH decreases