H2SO4 + FeSO4 + HIO3 = H2O + I2 + Fe2(SO4)3

H_2SO_4 (sulfuric acid) + FeSO_4 (duretter) + HIO_3 (iodic acid) ⟶ H_2O (water) + I_2 (iodine) + Fe_2(SO_4)_3·xH_2O (iron(III) sulfate hydrate)

Balance the chemical equation algebraically: H_2SO_4 + FeSO_4 + HIO_3 ⟶ H_2O + I_2 + Fe_2(SO_4)_3·xH_2O Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2SO_4 + c_2 FeSO_4 + c_3 HIO_3 ⟶ c_4 H_2O + c_5 I_2 + c_6 Fe_2(SO_4)_3·xH_2O Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, S, Fe and I: H: | 2 c_1 + c_3 = 2 c_4 O: | 4 c_1 + 4 c_2 + 3 c_3 = c_4 + 12 c_6 S: | c_1 + c_2 = 3 c_6 Fe: | c_2 = 2 c_6 I: | c_3 = 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_5 = 1 and solve the system of equations for the remaining coefficients: c_1 = 5 c_2 = 10 c_3 = 2 c_4 = 6 c_5 = 1 c_6 = 5 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 5 H_2SO_4 + 10 FeSO_4 + 2 HIO_3 ⟶ 6 H_2O + I_2 + 5 Fe_2(SO_4)_3·xH_2O

+ + ⟶ + +

sulfuric acid + duretter + iodic acid ⟶ water + iodine + iron(III) sulfate hydrate

Construct the equilibrium constant, K, expression for: H_2SO_4 + FeSO_4 + HIO_3 ⟶ H_2O + I_2 + Fe_2(SO_4)_3·xH_2O 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 H_2SO_4 + 10 FeSO_4 + 2 HIO_3 ⟶ 6 H_2O + I_2 + 5 Fe_2(SO_4)_3·xH_2O 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 H_2SO_4 | 5 | -5 FeSO_4 | 10 | -10 HIO_3 | 2 | -2 H_2O | 6 | 6 I_2 | 1 | 1 Fe_2(SO_4)_3·xH_2O | 5 | 5 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2SO_4 | 5 | -5 | ([H2SO4])^(-5) FeSO_4 | 10 | -10 | ([FeSO4])^(-10) HIO_3 | 2 | -2 | ([HIO3])^(-2) H_2O | 6 | 6 | ([H2O])^6 I_2 | 1 | 1 | [I2] Fe_2(SO_4)_3·xH_2O | 5 | 5 | ([Fe2(SO4)3·xH2O])^5 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 = ([H2SO4])^(-5) ([FeSO4])^(-10) ([HIO3])^(-2) ([H2O])^6 [I2] ([Fe2(SO4)3·xH2O])^5 = (([H2O])^6 [I2] ([Fe2(SO4)3·xH2O])^5)/(([H2SO4])^5 ([FeSO4])^10 ([HIO3])^2)

Construct the rate of reaction expression for: H_2SO_4 + FeSO_4 + HIO_3 ⟶ H_2O + I_2 + Fe_2(SO_4)_3·xH_2O 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 H_2SO_4 + 10 FeSO_4 + 2 HIO_3 ⟶ 6 H_2O + I_2 + 5 Fe_2(SO_4)_3·xH_2O 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 H_2SO_4 | 5 | -5 FeSO_4 | 10 | -10 HIO_3 | 2 | -2 H_2O | 6 | 6 I_2 | 1 | 1 Fe_2(SO_4)_3·xH_2O | 5 | 5 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 H_2SO_4 | 5 | -5 | -1/5 (Δ[H2SO4])/(Δt) FeSO_4 | 10 | -10 | -1/10 (Δ[FeSO4])/(Δt) HIO_3 | 2 | -2 | -1/2 (Δ[HIO3])/(Δt) H_2O | 6 | 6 | 1/6 (Δ[H2O])/(Δt) I_2 | 1 | 1 | (Δ[I2])/(Δt) Fe_2(SO_4)_3·xH_2O | 5 | 5 | 1/5 (Δ[Fe2(SO4)3·xH2O])/(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[H2SO4])/(Δt) = -1/10 (Δ[FeSO4])/(Δt) = -1/2 (Δ[HIO3])/(Δt) = 1/6 (Δ[H2O])/(Δt) = (Δ[I2])/(Δt) = 1/5 (Δ[Fe2(SO4)3·xH2O])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sulfuric acid | duretter | iodic acid | water | iodine | iron(III) sulfate hydrate formula | H_2SO_4 | FeSO_4 | HIO_3 | H_2O | I_2 | Fe_2(SO_4)_3·xH_2O Hill formula | H_2O_4S | FeO_4S | HIO_3 | H_2O | I_2 | Fe_2O_12S_3 name | sulfuric acid | duretter | iodic acid | water | iodine | iron(III) sulfate hydrate IUPAC name | sulfuric acid | iron(+2) cation sulfate | iodic acid | water | molecular iodine | diferric trisulfate

| sulfuric acid | duretter | iodic acid | water | iodine | iron(III) sulfate hydrate molar mass | 98.07 g/mol | 151.9 g/mol | 175.91 g/mol | 18.015 g/mol | 253.80894 g/mol | 399.9 g/mol phase | liquid (at STP) | | solid (at STP) | liquid (at STP) | solid (at STP) | melting point | 10.371 °C | | 110 °C | 0 °C | 113 °C | boiling point | 279.6 °C | | | 99.9839 °C | 184 °C | density | 1.8305 g/cm^3 | 2.841 g/cm^3 | 4.629 g/cm^3 | 1 g/cm^3 | 4.94 g/cm^3 | solubility in water | very soluble | | very soluble | | | slightly soluble surface tension | 0.0735 N/m | | | 0.0728 N/m | | dynamic viscosity | 0.021 Pa s (at 25 °C) | | | 8.9×10^-4 Pa s (at 25 °C) | 0.00227 Pa s (at 116 °C) | odor | odorless | | | odorless | |