NaOH + FeCl3 = NaCl + Fe(OH)3

NaOH (sodium hydroxide) + FeCl_3 (iron(III) chloride) ⟶ NaCl (sodium chloride) + Fe(OH)_3 (iron(III) hydroxide)

Balance the chemical equation algebraically: NaOH + FeCl_3 ⟶ NaCl + Fe(OH)_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 NaOH + c_2 FeCl_3 ⟶ c_3 NaCl + c_4 Fe(OH)_3 Set the number of atoms in the reactants equal to the number of atoms in the products for H, Na, O, Cl and Fe: H: | c_1 = 3 c_4 Na: | c_1 = c_3 O: | c_1 = 3 c_4 Cl: | 3 c_2 = c_3 Fe: | 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 3 c_2 = 1 c_3 = 3 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 3 NaOH + FeCl_3 ⟶ 3 NaCl + Fe(OH)_3

+ ⟶ +

sodium hydroxide + iron(III) chloride ⟶ sodium chloride + iron(III) hydroxide

Construct the equilibrium constant, K, expression for: NaOH + FeCl_3 ⟶ NaCl + Fe(OH)_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: 3 NaOH + FeCl_3 ⟶ 3 NaCl + Fe(OH)_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 | 3 | -3 FeCl_3 | 1 | -1 NaCl | 3 | 3 Fe(OH)_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 | 3 | -3 | ([NaOH])^(-3) FeCl_3 | 1 | -1 | ([FeCl3])^(-1) NaCl | 3 | 3 | ([NaCl])^3 Fe(OH)_3 | 1 | 1 | [Fe(OH)3] 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])^(-3) ([FeCl3])^(-1) ([NaCl])^3 [Fe(OH)3] = (([NaCl])^3 [Fe(OH)3])/(([NaOH])^3 [FeCl3])

Construct the rate of reaction expression for: NaOH + FeCl_3 ⟶ NaCl + Fe(OH)_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: 3 NaOH + FeCl_3 ⟶ 3 NaCl + Fe(OH)_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 | 3 | -3 FeCl_3 | 1 | -1 NaCl | 3 | 3 Fe(OH)_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 | 3 | -3 | -1/3 (Δ[NaOH])/(Δt) FeCl_3 | 1 | -1 | -(Δ[FeCl3])/(Δt) NaCl | 3 | 3 | 1/3 (Δ[NaCl])/(Δt) Fe(OH)_3 | 1 | 1 | (Δ[Fe(OH)3])/(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 = -1/3 (Δ[NaOH])/(Δt) = -(Δ[FeCl3])/(Δt) = 1/3 (Δ[NaCl])/(Δt) = (Δ[Fe(OH)3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sodium hydroxide | iron(III) chloride | sodium chloride | iron(III) hydroxide formula | NaOH | FeCl_3 | NaCl | Fe(OH)_3 Hill formula | HNaO | Cl_3Fe | ClNa | FeH_3O_3 name | sodium hydroxide | iron(III) chloride | sodium chloride | iron(III) hydroxide IUPAC name | sodium hydroxide | trichloroiron | sodium chloride | ferric trihydroxide

| sodium hydroxide | iron(III) chloride | sodium chloride | iron(III) hydroxide molar mass | 39.997 g/mol | 162.2 g/mol | 58.44 g/mol | 106.87 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | melting point | 323 °C | 304 °C | 801 °C | boiling point | 1390 °C | | 1413 °C | density | 2.13 g/cm^3 | | 2.16 g/cm^3 | solubility in water | soluble | | soluble | surface tension | 0.07435 N/m | | | dynamic viscosity | 0.004 Pa s (at 350 °C) | | | odor | | | odorless |