HNO3 + NaCl = H2O + NO2 + NaNO3 + HClO

HNO_3 nitric acid + NaCl sodium chloride ⟶ H_2O water + NO_2 nitrogen dioxide + NaNO_3 sodium nitrate + HOCl hypochlorous acid

Balance the chemical equation algebraically: HNO_3 + NaCl ⟶ H_2O + NO_2 + NaNO_3 + HOCl Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HNO_3 + c_2 NaCl ⟶ c_3 H_2O + c_4 NO_2 + c_5 NaNO_3 + c_6 HOCl Set the number of atoms in the reactants equal to the number of atoms in the products for H, N, O, Cl and Na: H: | c_1 = 2 c_3 + c_6 N: | c_1 = c_4 + c_5 O: | 3 c_1 = c_3 + 2 c_4 + 3 c_5 + c_6 Cl: | c_2 = c_6 Na: | c_2 = c_5 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 3 c_2 = 1 c_3 = 1 c_4 = 2 c_5 = 1 c_6 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 3 HNO_3 + NaCl ⟶ H_2O + 2 NO_2 + NaNO_3 + HOCl

+ ⟶ + + +

nitric acid + sodium chloride ⟶ water + nitrogen dioxide + sodium nitrate + hypochlorous acid

Construct the equilibrium constant, K, expression for: HNO_3 + NaCl ⟶ H_2O + NO_2 + NaNO_3 + HOCl 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 HNO_3 + NaCl ⟶ H_2O + 2 NO_2 + NaNO_3 + HOCl 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 HNO_3 | 3 | -3 NaCl | 1 | -1 H_2O | 1 | 1 NO_2 | 2 | 2 NaNO_3 | 1 | 1 HOCl | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HNO_3 | 3 | -3 | ([HNO3])^(-3) NaCl | 1 | -1 | ([NaCl])^(-1) H_2O | 1 | 1 | [H2O] NO_2 | 2 | 2 | ([NO2])^2 NaNO_3 | 1 | 1 | [NaNO3] HOCl | 1 | 1 | [HOCl] 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 = ([HNO3])^(-3) ([NaCl])^(-1) [H2O] ([NO2])^2 [NaNO3] [HOCl] = ([H2O] ([NO2])^2 [NaNO3] [HOCl])/(([HNO3])^3 [NaCl])

Construct the rate of reaction expression for: HNO_3 + NaCl ⟶ H_2O + NO_2 + NaNO_3 + HOCl 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 HNO_3 + NaCl ⟶ H_2O + 2 NO_2 + NaNO_3 + HOCl 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 HNO_3 | 3 | -3 NaCl | 1 | -1 H_2O | 1 | 1 NO_2 | 2 | 2 NaNO_3 | 1 | 1 HOCl | 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 HNO_3 | 3 | -3 | -1/3 (Δ[HNO3])/(Δt) NaCl | 1 | -1 | -(Δ[NaCl])/(Δt) H_2O | 1 | 1 | (Δ[H2O])/(Δt) NO_2 | 2 | 2 | 1/2 (Δ[NO2])/(Δt) NaNO_3 | 1 | 1 | (Δ[NaNO3])/(Δt) HOCl | 1 | 1 | (Δ[HOCl])/(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[HNO3])/(Δt) = -(Δ[NaCl])/(Δt) = (Δ[H2O])/(Δt) = 1/2 (Δ[NO2])/(Δt) = (Δ[NaNO3])/(Δt) = (Δ[HOCl])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| nitric acid | sodium chloride | water | nitrogen dioxide | sodium nitrate | hypochlorous acid formula | HNO_3 | NaCl | H_2O | NO_2 | NaNO_3 | HOCl Hill formula | HNO_3 | ClNa | H_2O | NO_2 | NNaO_3 | ClHO name | nitric acid | sodium chloride | water | nitrogen dioxide | sodium nitrate | hypochlorous acid IUPAC name | nitric acid | sodium chloride | water | Nitrogen dioxide | sodium nitrate | hypochlorous acid