Question

pH of a 0.02 molar solution of hydrochloric acid is

Answer 1

Since HCl is a strong acid it completely dissociates. Therefore all the H+ protonates water molecules to give H3O+. Its concentration here is high enough to ignore H3O+ contribution from water so the pH is just -log(0.02) = 1.7. pH + pOH = 14 so the pOH is 12.3.