Hypochlorous acid (HOCl) is produced when chlorine gas (Cl₂) dissolves in water:
Cl₂(g) + H₂O(l) ⇌ HOCl(aq) + HCl(aq)
The solubility of chlorine in water at 30 °C is 0.576 g/100 mL. Calculate the pH and the concentrations of all species (H₃O⁺, OH^–, HOCl, OCl^–, and Cl^–) in a saturated chlorine solution at this temperature. Assume that all chlorine reacts with water. (K_a of HOCl = 2.95×10^–8)

• A. [H₃O⁺] = 0.0775 M [OH^–] = 1.23×10^–13 M [HOCl] = 0.0847 M [OCl^–] = 2.95×10^–8 M [Cl^–] = 0.0812 M pH = 1.117
• B. [H₃O⁺] = 0.0775 M [OH^–] = 1.23×10^–13 M [HOCl] = 0.0847 M [OCl^–] = 2.12×10^–8 M [Cl^–] = 0.0873 M pH = 1.883
• C. [H₃O⁺] = 0.0812 M [OH^–] = 1.23×10^–13 M [HOCl] = 0.0812 M [OCl^–] = 2.95×10^–8 M [Cl^–] = 0.0812 M pH = 1.090
• D. [H₃O⁺] = 0.0975 M [OH^–] = 4.23×10^–13 M [HOCl] = 0.0847 M [OCl^–] = 2.12×10^–8 M [Cl^–] = 0.0873 M pH = 1.883