NaI + HOCl = HCl + NaIO3

NaI sodium iodide + HOCl hypochlorous acid ⟶ HCl hydrogen chloride + NaIO_3 sodium iodate

Balance the chemical equation algebraically: NaI + HOCl ⟶ HCl + NaIO_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 NaI + c_2 HOCl ⟶ c_3 HCl + c_4 NaIO_3 Set the number of atoms in the reactants equal to the number of atoms in the products for I, Na, Cl, H and O: I: | c_1 = c_4 Na: | c_1 = c_4 Cl: | c_2 = c_3 H: | c_2 = c_3 O: | c_2 = 3 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_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 3 c_3 = 3 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | NaI + 3 HOCl ⟶ 3 HCl + NaIO_3

+ ⟶ +

sodium iodide + hypochlorous acid ⟶ hydrogen chloride + sodium iodate

Construct the equilibrium constant, K, expression for: NaI + HOCl ⟶ HCl + NaIO_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: NaI + 3 HOCl ⟶ 3 HCl + NaIO_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 NaI | 1 | -1 HOCl | 3 | -3 HCl | 3 | 3 NaIO_3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression NaI | 1 | -1 | ([NaI])^(-1) HOCl | 3 | -3 | ([HOCl])^(-3) HCl | 3 | 3 | ([HCl])^3 NaIO_3 | 1 | 1 | [NaIO3] 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 = ([NaI])^(-1) ([HOCl])^(-3) ([HCl])^3 [NaIO3] = (([HCl])^3 [NaIO3])/([NaI] ([HOCl])^3)

Construct the rate of reaction expression for: NaI + HOCl ⟶ HCl + NaIO_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: NaI + 3 HOCl ⟶ 3 HCl + NaIO_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 NaI | 1 | -1 HOCl | 3 | -3 HCl | 3 | 3 NaIO_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 NaI | 1 | -1 | -(Δ[NaI])/(Δt) HOCl | 3 | -3 | -1/3 (Δ[HOCl])/(Δt) HCl | 3 | 3 | 1/3 (Δ[HCl])/(Δt) NaIO_3 | 1 | 1 | (Δ[NaIO3])/(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[NaI])/(Δt) = -1/3 (Δ[HOCl])/(Δt) = 1/3 (Δ[HCl])/(Δt) = (Δ[NaIO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sodium iodide | hypochlorous acid | hydrogen chloride | sodium iodate formula | NaI | HOCl | HCl | NaIO_3 Hill formula | INa | ClHO | ClH | INaO_3 name | sodium iodide | hypochlorous acid | hydrogen chloride | sodium iodate

| sodium iodide | hypochlorous acid | hydrogen chloride | sodium iodate molar mass | 149.89424 g/mol | 52.46 g/mol | 36.46 g/mol | 197.891 g/mol phase | solid (at STP) | | gas (at STP) | solid (at STP) melting point | 661 °C | | -114.17 °C | 425 °C boiling point | 1300 °C | | -85 °C | density | 3.67 g/cm^3 | | 0.00149 g/cm^3 (at 25 °C) | 3.56 g/cm^3 solubility in water | | soluble | miscible | dynamic viscosity | 0.0010446 Pa s (at 691 °C) | | |