Determine the resulting pH when 75 mL of 0.05M HBr is reacted with 74 mL of 0.075 M KOH

pH = 12.08

Explanation:

First we calculate how many moles of each substance were added, using the given volume and concentration:

As HBr is a strong acid, it dissociates completely into H⁺ and Br⁻ species. Conversely, KOH dissociates completely into OH⁻ and K⁺ species.

As there are more OH⁻ moles than H⁺ moles (5.55 vs 3.75), we calculate how many OH⁻ moles remain after the reaction:

With that number of moles and the volume of the mixture, we calculate [OH⁻]:

With [OH⁻], we calculate the pOH:

With the pOH, we calculate the pH: