H2SO4 + PbO2 + HNO2 = H2O + HNO3 + PbSO4

H_2SO_4 sulfuric acid + PbO_2 lead dioxide + HNO_2 nitrous acid ⟶ H_2O water + HNO_3 nitric acid + PbSO_4 lead(II) sulfate

Balance the chemical equation algebraically: H_2SO_4 + PbO_2 + HNO_2 ⟶ H_2O + HNO_3 + PbSO_4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2SO_4 + c_2 PbO_2 + c_3 HNO_2 ⟶ c_4 H_2O + c_5 HNO_3 + c_6 PbSO_4 Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, S, Pb and N: H: | 2 c_1 + c_3 = 2 c_4 + c_5 O: | 4 c_1 + 2 c_2 + 2 c_3 = c_4 + 3 c_5 + 4 c_6 S: | c_1 = c_6 Pb: | c_2 = c_6 N: | c_3 = 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_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 1 c_3 = 1 c_4 = 1 c_5 = 1 c_6 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | H_2SO_4 + PbO_2 + HNO_2 ⟶ H_2O + HNO_3 + PbSO_4

+ + ⟶ + +

sulfuric acid + lead dioxide + nitrous acid ⟶ water + nitric acid + lead(II) sulfate

Construct the equilibrium constant, K, expression for: H_2SO_4 + PbO_2 + HNO_2 ⟶ H_2O + HNO_3 + PbSO_4 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: H_2SO_4 + PbO_2 + HNO_2 ⟶ H_2O + HNO_3 + PbSO_4 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 H_2SO_4 | 1 | -1 PbO_2 | 1 | -1 HNO_2 | 1 | -1 H_2O | 1 | 1 HNO_3 | 1 | 1 PbSO_4 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2SO_4 | 1 | -1 | ([H2SO4])^(-1) PbO_2 | 1 | -1 | ([PbO2])^(-1) HNO_2 | 1 | -1 | ([HNO2])^(-1) H_2O | 1 | 1 | [H2O] HNO_3 | 1 | 1 | [HNO3] PbSO_4 | 1 | 1 | [PbSO4] 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 = ([H2SO4])^(-1) ([PbO2])^(-1) ([HNO2])^(-1) [H2O] [HNO3] [PbSO4] = ([H2O] [HNO3] [PbSO4])/([H2SO4] [PbO2] [HNO2])

Construct the rate of reaction expression for: H_2SO_4 + PbO_2 + HNO_2 ⟶ H_2O + HNO_3 + PbSO_4 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: H_2SO_4 + PbO_2 + HNO_2 ⟶ H_2O + HNO_3 + PbSO_4 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 H_2SO_4 | 1 | -1 PbO_2 | 1 | -1 HNO_2 | 1 | -1 H_2O | 1 | 1 HNO_3 | 1 | 1 PbSO_4 | 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 H_2SO_4 | 1 | -1 | -(Δ[H2SO4])/(Δt) PbO_2 | 1 | -1 | -(Δ[PbO2])/(Δt) HNO_2 | 1 | -1 | -(Δ[HNO2])/(Δt) H_2O | 1 | 1 | (Δ[H2O])/(Δt) HNO_3 | 1 | 1 | (Δ[HNO3])/(Δt) PbSO_4 | 1 | 1 | (Δ[PbSO4])/(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[H2SO4])/(Δt) = -(Δ[PbO2])/(Δt) = -(Δ[HNO2])/(Δt) = (Δ[H2O])/(Δt) = (Δ[HNO3])/(Δt) = (Δ[PbSO4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sulfuric acid | lead dioxide | nitrous acid | water | nitric acid | lead(II) sulfate formula | H_2SO_4 | PbO_2 | HNO_2 | H_2O | HNO_3 | PbSO_4 Hill formula | H_2O_4S | O_2Pb | HNO_2 | H_2O | HNO_3 | O_4PbS name | sulfuric acid | lead dioxide | nitrous acid | water | nitric acid | lead(II) sulfate

| sulfuric acid | lead dioxide | nitrous acid | water | nitric acid | lead(II) sulfate molar mass | 98.07 g/mol | 239.2 g/mol | 47.013 g/mol | 18.015 g/mol | 63.012 g/mol | 303.3 g/mol phase | liquid (at STP) | solid (at STP) | | liquid (at STP) | liquid (at STP) | solid (at STP) melting point | 10.371 °C | 290 °C | | 0 °C | -41.6 °C | 1087 °C boiling point | 279.6 °C | | | 99.9839 °C | 83 °C | density | 1.8305 g/cm^3 | 9.58 g/cm^3 | | 1 g/cm^3 | 1.5129 g/cm^3 | 6.29 g/cm^3 solubility in water | very soluble | insoluble | | | miscible | slightly soluble surface tension | 0.0735 N/m | | | 0.0728 N/m | | dynamic viscosity | 0.021 Pa s (at 25 °C) | | | 8.9×10^-4 Pa s (at 25 °C) | 7.6×10^-4 Pa s (at 25 °C) | odor | odorless | | | odorless | |