HNO3 = O2 + H2 + NO2

HNO_3 nitric acid ⟶ O_2 oxygen + H_2 hydrogen + NO_2 nitrogen dioxide

Balance the chemical equation algebraically: HNO_3 ⟶ O_2 + H_2 + NO_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HNO_3 ⟶ c_2 O_2 + c_3 H_2 + c_4 NO_2 Set the number of atoms in the reactants equal to the number of atoms in the products for H, N and O: H: | c_1 = 2 c_3 N: | c_1 = c_4 O: | 3 c_1 = 2 c_2 + 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 = 1 c_4 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 HNO_3 ⟶ O_2 + H_2 + 2 NO_2