A weak acid,HF,is in solution with dissolved sodium fluoride,NaF.If HCl is added,which ion will react with the extra hydrogen ions from the HCl to keep the pH from changing? A)OH^- B)Na⁺ C)F^- D)Na^- E)none of these

Question

Quizplus · Accepted Answer

When HCl is added, it will dissociate into H+ and Cl-. Since HF is a weak acid, it will not completely dissociate, and some HF molecules will remain undissociated. The NaF will dissociate into Na+ and F-. The H+ ions from HCl will react with the F- ions from NaF to form HF. This will help to maintain the pH of the solution. Therefore, the ion that will react with the extra hydrogen ions from the HCl to keep the pH from changing is F-, which is represented in choice C.

A Weak Acid,HF,is in Solution with Dissolved Sodium Fluoride,NaF