HNO3 + Sb = H2O + NO + HSbO3

HNO_3 nitric acid + Sb gray antimony ⟶ H_2O water + NO nitric oxide + HSbO3

Balance the chemical equation algebraically: HNO_3 + Sb ⟶ H_2O + NO + HSbO3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HNO_3 + c_2 Sb ⟶ c_3 H_2O + c_4 NO + c_5 HSbO3 Set the number of atoms in the reactants equal to the number of atoms in the products for H, N, O and Sb: H: | c_1 = 2 c_3 + c_5 N: | c_1 = c_4 O: | 3 c_1 = c_3 + c_4 + 3 c_5 Sb: | 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_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 5 c_2 = 3 c_3 = 1 c_4 = 5 c_5 = 3 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 5 HNO_3 + 3 Sb ⟶ H_2O + 5 NO + 3 HSbO3

+ ⟶ + + HSbO3

nitric acid + gray antimony ⟶ water + nitric oxide + HSbO3

Construct the equilibrium constant, K, expression for: HNO_3 + Sb ⟶ H_2O + NO + HSbO3 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: 5 HNO_3 + 3 Sb ⟶ H_2O + 5 NO + 3 HSbO3 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 | 5 | -5 Sb | 3 | -3 H_2O | 1 | 1 NO | 5 | 5 HSbO3 | 3 | 3 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HNO_3 | 5 | -5 | ([HNO3])^(-5) Sb | 3 | -3 | ([Sb])^(-3) H_2O | 1 | 1 | [H2O] NO | 5 | 5 | ([NO])^5 HSbO3 | 3 | 3 | ([HSbO3])^3 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])^(-5) ([Sb])^(-3) [H2O] ([NO])^5 ([HSbO3])^3 = ([H2O] ([NO])^5 ([HSbO3])^3)/(([HNO3])^5 ([Sb])^3)

Construct the rate of reaction expression for: HNO_3 + Sb ⟶ H_2O + NO + HSbO3 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: 5 HNO_3 + 3 Sb ⟶ H_2O + 5 NO + 3 HSbO3 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 | 5 | -5 Sb | 3 | -3 H_2O | 1 | 1 NO | 5 | 5 HSbO3 | 3 | 3 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 | 5 | -5 | -1/5 (Δ[HNO3])/(Δt) Sb | 3 | -3 | -1/3 (Δ[Sb])/(Δt) H_2O | 1 | 1 | (Δ[H2O])/(Δt) NO | 5 | 5 | 1/5 (Δ[NO])/(Δt) HSbO3 | 3 | 3 | 1/3 (Δ[HSbO3])/(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 = -1/5 (Δ[HNO3])/(Δt) = -1/3 (Δ[Sb])/(Δt) = (Δ[H2O])/(Δt) = 1/5 (Δ[NO])/(Δt) = 1/3 (Δ[HSbO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| nitric acid | gray antimony | water | nitric oxide | HSbO3 formula | HNO_3 | Sb | H_2O | NO | HSbO3 Hill formula | HNO_3 | Sb | H_2O | NO | HO3Sb name | nitric acid | gray antimony | water | nitric oxide | IUPAC name | nitric acid | antimony | water | nitric oxide |

| nitric acid | gray antimony | water | nitric oxide | HSbO3 molar mass | 63.012 g/mol | 121.76 g/mol | 18.015 g/mol | 30.006 g/mol | 170.77 g/mol phase | liquid (at STP) | solid (at STP) | liquid (at STP) | gas (at STP) | melting point | -41.6 °C | 630 °C | 0 °C | -163.6 °C | boiling point | 83 °C | 1587 °C | 99.9839 °C | -151.7 °C | density | 1.5129 g/cm^3 | 6.69 g/cm^3 | 1 g/cm^3 | 0.001226 g/cm^3 (at 25 °C) | solubility in water | miscible | | | | surface tension | | | 0.0728 N/m | | dynamic viscosity | 7.6×10^-4 Pa s (at 25 °C) | | 8.9×10^-4 Pa s (at 25 °C) | 1.911×10^-5 Pa s (at 25 °C) | odor | | | odorless | |