CH3CH2OH + SOCl2 = HCl + SO2 + CH3CH2Cl

CH_3CH_2OH ethanol + SOCl_2 thionyl chloride ⟶ HCl hydrogen chloride + SO_2 sulfur dioxide + CH3CH2Cl

Balance the chemical equation algebraically: CH_3CH_2OH + SOCl_2 ⟶ HCl + SO_2 + CH3CH2Cl Add stoichiometric coefficients, c_i, to the reactants and products: c_1 CH_3CH_2OH + c_2 SOCl_2 ⟶ c_3 HCl + c_4 SO_2 + c_5 CH3CH2Cl Set the number of atoms in the reactants equal to the number of atoms in the products for C, H, O, Cl and S: C: | 2 c_1 = 2 c_5 H: | 6 c_1 = c_3 + 5 c_5 O: | c_1 + c_2 = 2 c_4 Cl: | 2 c_2 = c_3 + c_5 S: | c_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_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 1 c_3 = 1 c_4 = 1 c_5 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | CH_3CH_2OH + SOCl_2 ⟶ HCl + SO_2 + CH3CH2Cl

+ ⟶ + + CH3CH2Cl

ethanol + thionyl chloride ⟶ hydrogen chloride + sulfur dioxide + CH3CH2Cl

Construct the equilibrium constant, K, expression for: CH_3CH_2OH + SOCl_2 ⟶ HCl + SO_2 + CH3CH2Cl 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: CH_3CH_2OH + SOCl_2 ⟶ HCl + SO_2 + CH3CH2Cl 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 CH_3CH_2OH | 1 | -1 SOCl_2 | 1 | -1 HCl | 1 | 1 SO_2 | 1 | 1 CH3CH2Cl | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression CH_3CH_2OH | 1 | -1 | ([CH3CH2OH])^(-1) SOCl_2 | 1 | -1 | ([SOCl2])^(-1) HCl | 1 | 1 | [HCl] SO_2 | 1 | 1 | [SO2] CH3CH2Cl | 1 | 1 | [CH3CH2Cl] 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 = ([CH3CH2OH])^(-1) ([SOCl2])^(-1) [HCl] [SO2] [CH3CH2Cl] = ([HCl] [SO2] [CH3CH2Cl])/([CH3CH2OH] [SOCl2])

Construct the rate of reaction expression for: CH_3CH_2OH + SOCl_2 ⟶ HCl + SO_2 + CH3CH2Cl 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: CH_3CH_2OH + SOCl_2 ⟶ HCl + SO_2 + CH3CH2Cl 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 CH_3CH_2OH | 1 | -1 SOCl_2 | 1 | -1 HCl | 1 | 1 SO_2 | 1 | 1 CH3CH2Cl | 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 CH_3CH_2OH | 1 | -1 | -(Δ[CH3CH2OH])/(Δt) SOCl_2 | 1 | -1 | -(Δ[SOCl2])/(Δt) HCl | 1 | 1 | (Δ[HCl])/(Δt) SO_2 | 1 | 1 | (Δ[SO2])/(Δt) CH3CH2Cl | 1 | 1 | (Δ[CH3CH2Cl])/(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[CH3CH2OH])/(Δt) = -(Δ[SOCl2])/(Δt) = (Δ[HCl])/(Δt) = (Δ[SO2])/(Δt) = (Δ[CH3CH2Cl])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| ethanol | thionyl chloride | hydrogen chloride | sulfur dioxide | CH3CH2Cl formula | CH_3CH_2OH | SOCl_2 | HCl | SO_2 | CH3CH2Cl Hill formula | C_2H_6O | Cl_2OS | ClH | O_2S | C2H5Cl name | ethanol | thionyl chloride | hydrogen chloride | sulfur dioxide | IUPAC name | ethanol | thionyl dichloride | hydrogen chloride | sulfur dioxide |