Answer to Question #188083 in General Chemistry for Brooke

Question

explain why 0.20 M solutions of hydrobromic acid and hydrochloric acid have the same pH values but 0.20 M solutions of oxalic acid and hydrochloric acid have different pH values.

Answer 1

pH is a measure of how much hydrogen or hydronium ions of a substance dissociates in water.

In HCl and HBr, given constant concentration, there is an equal or almost equal amount of hydrogen ion given off in dissolution.

However, the same isn't so for oxalic acid (COOH)₂ which doss not dissociate and release the same amount of ions (positive or negative) with the rest given constant concentration.