NaOH + I2 = H2O + NaI + NaIO3

NaOH (sodium hydroxide) + I_2 (iodine) ⟶ H_2O (water) + NaI (sodium iodide) + NaIO_3 (sodium iodate)

Balance the chemical equation algebraically: NaOH + I_2 ⟶ H_2O + NaI + NaIO_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 NaOH + c_2 I_2 ⟶ c_3 H_2O + c_4 NaI + c_5 NaIO_3 Set the number of atoms in the reactants equal to the number of atoms in the products for H, Na, O and I: H: | c_1 = 2 c_3 Na: | c_1 = c_4 + c_5 O: | c_1 = c_3 + 3 c_5 I: | 2 c_2 = c_4 + 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_5 = 1 and solve the system of equations for the remaining coefficients: c_1 = 6 c_2 = 3 c_3 = 3 c_4 = 5 c_5 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 6 NaOH + 3 I_2 ⟶ 3 H_2O + 5 NaI + NaIO_3

+ ⟶ + +

sodium hydroxide + iodine ⟶ water + sodium iodide + sodium iodate

| sodium hydroxide | iodine | water | sodium iodide | sodium iodate molecular enthalpy | -425.8 kJ/mol | 0 kJ/mol | -285.8 kJ/mol | -287.8 kJ/mol | -481.8 kJ/mol total enthalpy | -2555 kJ/mol | 0 kJ/mol | -857.5 kJ/mol | -1439 kJ/mol | -481.8 kJ/mol | H_initial = -2555 kJ/mol | | H_final = -2778 kJ/mol | | ΔH_rxn^0 | -2778 kJ/mol - -2555 kJ/mol = -223.5 kJ/mol (exothermic) | | | |

Construct the equilibrium constant, K, expression for: NaOH + I_2 ⟶ H_2O + NaI + 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: 6 NaOH + 3 I_2 ⟶ 3 H_2O + 5 NaI + 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 NaOH | 6 | -6 I_2 | 3 | -3 H_2O | 3 | 3 NaI | 5 | 5 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 NaOH | 6 | -6 | ([NaOH])^(-6) I_2 | 3 | -3 | ([I2])^(-3) H_2O | 3 | 3 | ([H2O])^3 NaI | 5 | 5 | ([NaI])^5 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 = ([NaOH])^(-6) ([I2])^(-3) ([H2O])^3 ([NaI])^5 [NaIO3] = (([H2O])^3 ([NaI])^5 [NaIO3])/(([NaOH])^6 ([I2])^3)

Construct the rate of reaction expression for: NaOH + I_2 ⟶ H_2O + NaI + 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: 6 NaOH + 3 I_2 ⟶ 3 H_2O + 5 NaI + 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 NaOH | 6 | -6 I_2 | 3 | -3 H_2O | 3 | 3 NaI | 5 | 5 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 NaOH | 6 | -6 | -1/6 (Δ[NaOH])/(Δt) I_2 | 3 | -3 | -1/3 (Δ[I2])/(Δt) H_2O | 3 | 3 | 1/3 (Δ[H2O])/(Δt) NaI | 5 | 5 | 1/5 (Δ[NaI])/(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 = -1/6 (Δ[NaOH])/(Δt) = -1/3 (Δ[I2])/(Δt) = 1/3 (Δ[H2O])/(Δt) = 1/5 (Δ[NaI])/(Δt) = (Δ[NaIO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sodium hydroxide | iodine | water | sodium iodide | sodium iodate formula | NaOH | I_2 | H_2O | NaI | NaIO_3 Hill formula | HNaO | I_2 | H_2O | INa | INaO_3 name | sodium hydroxide | iodine | water | sodium iodide | sodium iodate IUPAC name | sodium hydroxide | molecular iodine | water | sodium iodide | sodium iodate

| sodium hydroxide | iodine | water | sodium iodide | sodium iodate molar mass | 39.997 g/mol | 253.80894 g/mol | 18.015 g/mol | 149.89424 g/mol | 197.891 g/mol phase | solid (at STP) | solid (at STP) | liquid (at STP) | solid (at STP) | solid (at STP) melting point | 323 °C | 113 °C | 0 °C | 661 °C | 425 °C boiling point | 1390 °C | 184 °C | 99.9839 °C | 1300 °C | density | 2.13 g/cm^3 | 4.94 g/cm^3 | 1 g/cm^3 | 3.67 g/cm^3 | 3.56 g/cm^3 solubility in water | soluble | | | | surface tension | 0.07435 N/m | | 0.0728 N/m | | dynamic viscosity | 0.004 Pa s (at 350 °C) | 0.00227 Pa s (at 116 °C) | 8.9×10^-4 Pa s (at 25 °C) | 0.0010446 Pa s (at 691 °C) | odor | | | odorless | |