HOCl = HCl + HClO3

HOCl hypochlorous acid ⟶ HCl hydrogen chloride + HClO3

Balance the chemical equation algebraically: HOCl ⟶ HCl + HClO3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HOCl ⟶ c_2 HCl + c_3 HClO3 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H and O: Cl: | c_1 = c_2 + c_3 H: | c_1 = c_2 + c_3 O: | c_1 = 3 c_3 Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 3 c_2 = 2 c_3 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 3 HOCl ⟶ 2 HCl + HClO3

⟶ + HClO3

hypochlorous acid ⟶ hydrogen chloride + HClO3

Construct the equilibrium constant, K, expression for: HOCl ⟶ HCl + HClO3 Plan: • Balance the chemical equation. • Determine the stoichiometric numbers. • Assemble the activity expression for each chemical species. • Use the activity expressions to build the equilibrium constant expression. Write the balanced chemical equation: 3 HOCl ⟶ 2 HCl + HClO3 Assign stoichiometric numbers, ν_i, using the stoichiometric coefficients, c_i, from the balanced chemical equation in the following manner: ν_i = -c_i for reactants and ν_i = c_i for products: chemical species | c_i | ν_i HOCl | 3 | -3 HCl | 2 | 2 HClO3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HOCl | 3 | -3 | ([HOCl])^(-3) HCl | 2 | 2 | ([HCl])^2 HClO3 | 1 | 1 | [HClO3] The equilibrium constant symbol in the concentration basis is: K_c Mulitply the activity expressions to arrive at the K_c expression: Answer: | | K_c = ([HOCl])^(-3) ([HCl])^2 [HClO3] = (([HCl])^2 [HClO3])/([HOCl])^3

Construct the rate of reaction expression for: HOCl ⟶ HCl + HClO3 Plan: • Balance the chemical equation. • Determine the stoichiometric numbers. • Assemble the rate term for each chemical species. • Write the rate of reaction expression. Write the balanced chemical equation: 3 HOCl ⟶ 2 HCl + HClO3 Assign stoichiometric numbers, ν_i, using the stoichiometric coefficients, c_i, from the balanced chemical equation in the following manner: ν_i = -c_i for reactants and ν_i = c_i for products: chemical species | c_i | ν_i HOCl | 3 | -3 HCl | 2 | 2 HClO3 | 1 | 1 The rate term for each chemical species, B_i, is 1/ν_i(Δ[B_i])/(Δt) where [B_i] is the amount concentration and t is time: chemical species | c_i | ν_i | rate term HOCl | 3 | -3 | -1/3 (Δ[HOCl])/(Δt) HCl | 2 | 2 | 1/2 (Δ[HCl])/(Δt) HClO3 | 1 | 1 | (Δ[HClO3])/(Δt) (for infinitesimal rate of change, replace Δ with d) Set the rate terms equal to each other to arrive at the rate expression: Answer: | | rate = -1/3 (Δ[HOCl])/(Δt) = 1/2 (Δ[HCl])/(Δt) = (Δ[HClO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| hypochlorous acid | hydrogen chloride | HClO3 formula | HOCl | HCl | HClO3 Hill formula | ClHO | ClH | HClO3 name | hypochlorous acid | hydrogen chloride |

| hypochlorous acid | hydrogen chloride | HClO3 molar mass | 52.46 g/mol | 36.46 g/mol | 84.45 g/mol phase | | gas (at STP) | melting point | | -114.17 °C | boiling point | | -85 °C | density | | 0.00149 g/cm^3 (at 25 °C) | solubility in water | soluble | miscible |