SO2 + HNO2 = H2SO4 + NO

SO_2 sulfur dioxide + HNO_2 nitrous acid ⟶ H_2SO_4 sulfuric acid + NO nitric oxide

Balance the chemical equation algebraically: SO_2 + HNO_2 ⟶ H_2SO_4 + NO Add stoichiometric coefficients, c_i, to the reactants and products: c_1 SO_2 + c_2 HNO_2 ⟶ c_3 H_2SO_4 + c_4 NO Set the number of atoms in the reactants equal to the number of atoms in the products for O, S, H and N: O: | 2 c_1 + 2 c_2 = 4 c_3 + c_4 S: | c_1 = c_3 H: | c_2 = 2 c_3 N: | c_2 = c_4 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_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 2 c_3 = 1 c_4 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | SO_2 + 2 HNO_2 ⟶ H_2SO_4 + 2 NO

+ ⟶ +

sulfur dioxide + nitrous acid ⟶ sulfuric acid + nitric oxide

Construct the equilibrium constant, K, expression for: SO_2 + HNO_2 ⟶ H_2SO_4 + NO 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: SO_2 + 2 HNO_2 ⟶ H_2SO_4 + 2 NO 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 SO_2 | 1 | -1 HNO_2 | 2 | -2 H_2SO_4 | 1 | 1 NO | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression SO_2 | 1 | -1 | ([SO2])^(-1) HNO_2 | 2 | -2 | ([HNO2])^(-2) H_2SO_4 | 1 | 1 | [H2SO4] NO | 2 | 2 | ([NO])^2 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 = ([SO2])^(-1) ([HNO2])^(-2) [H2SO4] ([NO])^2 = ([H2SO4] ([NO])^2)/([SO2] ([HNO2])^2)

Construct the rate of reaction expression for: SO_2 + HNO_2 ⟶ H_2SO_4 + NO 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: SO_2 + 2 HNO_2 ⟶ H_2SO_4 + 2 NO 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 SO_2 | 1 | -1 HNO_2 | 2 | -2 H_2SO_4 | 1 | 1 NO | 2 | 2 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 SO_2 | 1 | -1 | -(Δ[SO2])/(Δt) HNO_2 | 2 | -2 | -1/2 (Δ[HNO2])/(Δt) H_2SO_4 | 1 | 1 | (Δ[H2SO4])/(Δt) NO | 2 | 2 | 1/2 (Δ[NO])/(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 = -(Δ[SO2])/(Δt) = -1/2 (Δ[HNO2])/(Δt) = (Δ[H2SO4])/(Δt) = 1/2 (Δ[NO])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sulfur dioxide | nitrous acid | sulfuric acid | nitric oxide formula | SO_2 | HNO_2 | H_2SO_4 | NO Hill formula | O_2S | HNO_2 | H_2O_4S | NO name | sulfur dioxide | nitrous acid | sulfuric acid | nitric oxide