Calculate the hydrogen ion concentration, [H+], for each of the following materials: Coffee, pH 5, Gastric juice, pH 2, Tomato Sauce, pH 3

Calculate the hydroxide ion concentration, [OH-], for which of the following materials?

A) Saltwater, pH 8
B) Bleach, pH 12
C) Lemon juice, pH 2
D) Milk, pH 6