NaOH + NH4Cl = NaCl + NH4OH

NaOH sodium hydroxide + NH_4Cl ammonium chloride ⟶ NaCl sodium chloride + NH_4OH ammonium hydroxide

Balance the chemical equation algebraically: NaOH + NH_4Cl ⟶ NaCl + NH_4OH Add stoichiometric coefficients, c_i, to the reactants and products: c_1 NaOH + c_2 NH_4Cl ⟶ c_3 NaCl + c_4 NH_4OH Set the number of atoms in the reactants equal to the number of atoms in the products for H, Na, O, Cl and N: H: | c_1 + 4 c_2 = 5 c_4 Na: | c_1 = c_3 O: | c_1 = c_4 Cl: | c_2 = c_3 N: | 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 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | NaOH + NH_4Cl ⟶ NaCl + NH_4OH

+ ⟶ +

sodium hydroxide + ammonium chloride ⟶ sodium chloride + ammonium hydroxide

Construct the equilibrium constant, K, expression for: NaOH + NH_4Cl ⟶ NaCl + NH_4OH 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: NaOH + NH_4Cl ⟶ NaCl + NH_4OH 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 | 1 | -1 NH_4Cl | 1 | -1 NaCl | 1 | 1 NH_4OH | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression NaOH | 1 | -1 | ([NaOH])^(-1) NH_4Cl | 1 | -1 | ([NH4Cl])^(-1) NaCl | 1 | 1 | [NaCl] NH_4OH | 1 | 1 | [NH4OH] 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])^(-1) ([NH4Cl])^(-1) [NaCl] [NH4OH] = ([NaCl] [NH4OH])/([NaOH] [NH4Cl])

Construct the rate of reaction expression for: NaOH + NH_4Cl ⟶ NaCl + NH_4OH 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: NaOH + NH_4Cl ⟶ NaCl + NH_4OH 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 | 1 | -1 NH_4Cl | 1 | -1 NaCl | 1 | 1 NH_4OH | 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 | 1 | -1 | -(Δ[NaOH])/(Δt) NH_4Cl | 1 | -1 | -(Δ[NH4Cl])/(Δt) NaCl | 1 | 1 | (Δ[NaCl])/(Δt) NH_4OH | 1 | 1 | (Δ[NH4OH])/(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[NaOH])/(Δt) = -(Δ[NH4Cl])/(Δt) = (Δ[NaCl])/(Δt) = (Δ[NH4OH])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sodium hydroxide | ammonium chloride | sodium chloride | ammonium hydroxide formula | NaOH | NH_4Cl | NaCl | NH_4OH Hill formula | HNaO | ClH_4N | ClNa | H_5NO name | sodium hydroxide | ammonium chloride | sodium chloride | ammonium hydroxide

| sodium hydroxide | ammonium chloride | sodium chloride | ammonium hydroxide molar mass | 39.997 g/mol | 53.49 g/mol | 58.44 g/mol | 35.046 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | aqueous (at STP) melting point | 323 °C | 340 °C | 801 °C | -57.5 °C boiling point | 1390 °C | | 1413 °C | 36 °C density | 2.13 g/cm^3 | 1.5256 g/cm^3 | 2.16 g/cm^3 | 0.9 g/cm^3 solubility in water | soluble | soluble | soluble | very soluble surface tension | 0.07435 N/m | | | dynamic viscosity | 0.004 Pa s (at 350 °C) | | | odor | | | odorless |