HCl + KMnO4 = Cl2 + KCl + H2O2 + MnCl2

HCl hydrogen chloride + KMnO_4 potassium permanganate ⟶ Cl_2 chlorine + KCl potassium chloride + H_2O_2 hydrogen peroxide + MnCl_2 manganese(II) chloride

Balance the chemical equation algebraically: HCl + KMnO_4 ⟶ Cl_2 + KCl + H_2O_2 + MnCl_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HCl + c_2 KMnO_4 ⟶ c_3 Cl_2 + c_4 KCl + c_5 H_2O_2 + c_6 MnCl_2 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H, K, Mn and O: Cl: | c_1 = 2 c_3 + c_4 + 2 c_6 H: | c_1 = 2 c_5 K: | c_2 = c_4 Mn: | c_2 = c_6 O: | 4 c_2 = 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_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 8 c_2 = 2 c_3 = 1 c_4 = 2 c_5 = 4 c_6 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 8 HCl + 2 KMnO_4 ⟶ Cl_2 + 2 KCl + 4 H_2O_2 + 2 MnCl_2

+ ⟶ + + +

hydrogen chloride + potassium permanganate ⟶ chlorine + potassium chloride + hydrogen peroxide + manganese(II) chloride

| hydrogen chloride | potassium permanganate | chlorine | potassium chloride | hydrogen peroxide | manganese(II) chloride molecular free energy | -95.3 kJ/mol | -737.6 kJ/mol | 0 kJ/mol | -408.5 kJ/mol | -120.4 kJ/mol | -440.5 kJ/mol total free energy | -762.4 kJ/mol | -1475 kJ/mol | 0 kJ/mol | -817 kJ/mol | -481.6 kJ/mol | -881 kJ/mol | G_initial = -2238 kJ/mol | | G_final = -2180 kJ/mol | | | ΔG_rxn^0 | -2180 kJ/mol - -2238 kJ/mol = 58 kJ/mol (endergonic) | | | | |

Construct the equilibrium constant, K, expression for: HCl + KMnO_4 ⟶ Cl_2 + KCl + H_2O_2 + MnCl_2 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: 8 HCl + 2 KMnO_4 ⟶ Cl_2 + 2 KCl + 4 H_2O_2 + 2 MnCl_2 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 HCl | 8 | -8 KMnO_4 | 2 | -2 Cl_2 | 1 | 1 KCl | 2 | 2 H_2O_2 | 4 | 4 MnCl_2 | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HCl | 8 | -8 | ([HCl])^(-8) KMnO_4 | 2 | -2 | ([KMnO4])^(-2) Cl_2 | 1 | 1 | [Cl2] KCl | 2 | 2 | ([KCl])^2 H_2O_2 | 4 | 4 | ([H2O2])^4 MnCl_2 | 2 | 2 | ([MnCl2])^2 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 = ([HCl])^(-8) ([KMnO4])^(-2) [Cl2] ([KCl])^2 ([H2O2])^4 ([MnCl2])^2 = ([Cl2] ([KCl])^2 ([H2O2])^4 ([MnCl2])^2)/(([HCl])^8 ([KMnO4])^2)

Construct the rate of reaction expression for: HCl + KMnO_4 ⟶ Cl_2 + KCl + H_2O_2 + MnCl_2 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: 8 HCl + 2 KMnO_4 ⟶ Cl_2 + 2 KCl + 4 H_2O_2 + 2 MnCl_2 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 HCl | 8 | -8 KMnO_4 | 2 | -2 Cl_2 | 1 | 1 KCl | 2 | 2 H_2O_2 | 4 | 4 MnCl_2 | 2 | 2 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 HCl | 8 | -8 | -1/8 (Δ[HCl])/(Δt) KMnO_4 | 2 | -2 | -1/2 (Δ[KMnO4])/(Δt) Cl_2 | 1 | 1 | (Δ[Cl2])/(Δt) KCl | 2 | 2 | 1/2 (Δ[KCl])/(Δt) H_2O_2 | 4 | 4 | 1/4 (Δ[H2O2])/(Δt) MnCl_2 | 2 | 2 | 1/2 (Δ[MnCl2])/(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 = -1/8 (Δ[HCl])/(Δt) = -1/2 (Δ[KMnO4])/(Δt) = (Δ[Cl2])/(Δt) = 1/2 (Δ[KCl])/(Δt) = 1/4 (Δ[H2O2])/(Δt) = 1/2 (Δ[MnCl2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| hydrogen chloride | potassium permanganate | chlorine | potassium chloride | hydrogen peroxide | manganese(II) chloride formula | HCl | KMnO_4 | Cl_2 | KCl | H_2O_2 | MnCl_2 Hill formula | ClH | KMnO_4 | Cl_2 | ClK | H_2O_2 | Cl_2Mn name | hydrogen chloride | potassium permanganate | chlorine | potassium chloride | hydrogen peroxide | manganese(II) chloride IUPAC name | hydrogen chloride | potassium permanganate | molecular chlorine | potassium chloride | hydrogen peroxide | dichloromanganese

| hydrogen chloride | potassium permanganate | chlorine | potassium chloride | hydrogen peroxide | manganese(II) chloride molar mass | 36.46 g/mol | 158.03 g/mol | 70.9 g/mol | 74.55 g/mol | 34.014 g/mol | 125.8 g/mol phase | gas (at STP) | solid (at STP) | gas (at STP) | solid (at STP) | liquid (at STP) | solid (at STP) melting point | -114.17 °C | 240 °C | -101 °C | 770 °C | -0.43 °C | 652 °C boiling point | -85 °C | | -34 °C | 1420 °C | 150.2 °C | density | 0.00149 g/cm^3 (at 25 °C) | 1 g/cm^3 | 0.003214 g/cm^3 (at 0 °C) | 1.98 g/cm^3 | 1.44 g/cm^3 | 2.98 g/cm^3 solubility in water | miscible | | | soluble | miscible | surface tension | | | | | 0.0804 N/m | dynamic viscosity | | | | | 0.001249 Pa s (at 20 °C) | odor | | odorless | | odorless | |