HCl + Na2SO3 = NaCl + H2SO3

HCl hydrogen chloride + Na_2SO_3 sodium sulfite ⟶ NaCl sodium chloride + H_2SO_3 sulfurous acid

Balance the chemical equation algebraically: HCl + Na_2SO_3 ⟶ NaCl + H_2SO_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HCl + c_2 Na_2SO_3 ⟶ c_3 NaCl + c_4 H_2SO_3 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H, Na, O and S: Cl: | c_1 = c_3 H: | c_1 = 2 c_4 Na: | 2 c_2 = c_3 O: | 3 c_2 = 3 c_4 S: | 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 1 c_3 = 2 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 HCl + Na_2SO_3 ⟶ 2 NaCl + H_2SO_3

+ ⟶ +

hydrogen chloride + sodium sulfite ⟶ sodium chloride + sulfurous acid

Construct the equilibrium constant, K, expression for: HCl + Na_2SO_3 ⟶ NaCl + H_2SO_3 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: 2 HCl + Na_2SO_3 ⟶ 2 NaCl + H_2SO_3 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 HCl | 2 | -2 Na_2SO_3 | 1 | -1 NaCl | 2 | 2 H_2SO_3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HCl | 2 | -2 | ([HCl])^(-2) Na_2SO_3 | 1 | -1 | ([Na2SO3])^(-1) NaCl | 2 | 2 | ([NaCl])^2 H_2SO_3 | 1 | 1 | [H2SO3] 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 = ([HCl])^(-2) ([Na2SO3])^(-1) ([NaCl])^2 [H2SO3] = (([NaCl])^2 [H2SO3])/(([HCl])^2 [Na2SO3])

Construct the rate of reaction expression for: HCl + Na_2SO_3 ⟶ NaCl + H_2SO_3 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: 2 HCl + Na_2SO_3 ⟶ 2 NaCl + H_2SO_3 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 HCl | 2 | -2 Na_2SO_3 | 1 | -1 NaCl | 2 | 2 H_2SO_3 | 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 HCl | 2 | -2 | -1/2 (Δ[HCl])/(Δt) Na_2SO_3 | 1 | -1 | -(Δ[Na2SO3])/(Δt) NaCl | 2 | 2 | 1/2 (Δ[NaCl])/(Δt) H_2SO_3 | 1 | 1 | (Δ[H2SO3])/(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 = -1/2 (Δ[HCl])/(Δt) = -(Δ[Na2SO3])/(Δt) = 1/2 (Δ[NaCl])/(Δt) = (Δ[H2SO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| hydrogen chloride | sodium sulfite | sodium chloride | sulfurous acid formula | HCl | Na_2SO_3 | NaCl | H_2SO_3 Hill formula | ClH | Na_2O_3S | ClNa | H_2O_3S name | hydrogen chloride | sodium sulfite | sodium chloride | sulfurous acid IUPAC name | hydrogen chloride | disodium sulfite | sodium chloride | sulfurous acid

| hydrogen chloride | sodium sulfite | sodium chloride | sulfurous acid molar mass | 36.46 g/mol | 126.04 g/mol | 58.44 g/mol | 82.07 g/mol phase | gas (at STP) | solid (at STP) | solid (at STP) | melting point | -114.17 °C | 500 °C | 801 °C | boiling point | -85 °C | | 1413 °C | density | 0.00149 g/cm^3 (at 25 °C) | 2.63 g/cm^3 | 2.16 g/cm^3 | 1.03 g/cm^3 solubility in water | miscible | | soluble | very soluble odor | | | odorless |