H2O + HNO3 + As2O3 = NO2 + H3AsO4

H_2O water + HNO_3 nitric acid + As_2O_3 arsenic trioxide ⟶ NO_2 nitrogen dioxide + H_3AsO_4 arsenic acid, solid

Balance the chemical equation algebraically: H_2O + HNO_3 + As_2O_3 ⟶ NO_2 + H_3AsO_4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2O + c_2 HNO_3 + c_3 As_2O_3 ⟶ c_4 NO_2 + c_5 H_3AsO_4 Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, N and As: H: | 2 c_1 + c_2 = 3 c_5 O: | c_1 + 3 c_2 + 3 c_3 = 2 c_4 + 4 c_5 N: | c_2 = c_4 As: | 2 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 = 4 c_3 = 1 c_4 = 4 c_5 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | H_2O + 4 HNO_3 + As_2O_3 ⟶ 4 NO_2 + 2 H_3AsO_4

+ + ⟶ +

water + nitric acid + arsenic trioxide ⟶ nitrogen dioxide + arsenic acid, solid

K_c = ([NO2]^4 [H3AsO4]^2)/([H2O] [HNO3]^4 [As2O3])

rate = -(Δ[H2O])/(Δt) = -1/4 (Δ[HNO3])/(Δt) = -(Δ[As2O3])/(Δt) = 1/4 (Δ[NO2])/(Δt) = 1/2 (Δ[H3AsO4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| water | nitric acid | arsenic trioxide | nitrogen dioxide | arsenic acid, solid formula | H_2O | HNO_3 | As_2O_3 | NO_2 | H_3AsO_4 Hill formula | H_2O | HNO_3 | As_2O_3 | NO_2 | AsH_3O_4 name | water | nitric acid | arsenic trioxide | nitrogen dioxide | arsenic acid, solid IUPAC name | water | nitric acid | 2, 4, 5-trioxa-1, 3-diarsabicyclo[1.1.1]pentane | Nitrogen dioxide | arsoric acid

| water | nitric acid | arsenic trioxide | nitrogen dioxide | arsenic acid, solid molar mass | 18.015 g/mol | 63.012 g/mol | 197.84 g/mol | 46.005 g/mol | 141.94 g/mol phase | liquid (at STP) | liquid (at STP) | solid (at STP) | gas (at STP) | solid (at STP) melting point | 0 °C | -41.6 °C | 312 °C | -11 °C | 35.5 °C boiling point | 99.9839 °C | 83 °C | 465 °C | 21 °C | 160 °C density | 1 g/cm^3 | 1.5129 g/cm^3 | 4.15 g/cm^3 | 0.00188 g/cm^3 (at 25 °C) | 2.2 g/cm^3 solubility in water | | miscible | | reacts | surface tension | 0.0728 N/m | | | | dynamic viscosity | 8.9×10^-4 Pa s (at 25 °C) | 7.6×10^-4 Pa s (at 25 °C) | | 4.02×10^-4 Pa s (at 25 °C) | odor | odorless | | | |