Input interpretation
KI potassium iodide + HOCl hypochlorous acid ⟶ KOH potassium hydroxide + I_2 iodine + KCl potassium chloride
Balanced equation
Balance the chemical equation algebraically: KI + HOCl ⟶ KOH + I_2 + KCl Add stoichiometric coefficients, c_i, to the reactants and products: c_1 KI + c_2 HOCl ⟶ c_3 KOH + c_4 I_2 + c_5 KCl Set the number of atoms in the reactants equal to the number of atoms in the products for I, K, Cl, H and O: I: | c_1 = 2 c_4 K: | c_1 = c_3 + c_5 Cl: | c_2 = c_5 H: | c_2 = c_3 O: | c_2 = c_3 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 = 2 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: | | 2 KI + HOCl ⟶ KOH + I_2 + KCl
Structures
+ ⟶ + +
Names
potassium iodide + hypochlorous acid ⟶ potassium hydroxide + iodine + potassium chloride
Equilibrium constant
Construct the equilibrium constant, K, expression for: KI + HOCl ⟶ KOH + I_2 + KCl 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: 2 KI + HOCl ⟶ KOH + I_2 + KCl 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 KI | 2 | -2 HOCl | 1 | -1 KOH | 1 | 1 I_2 | 1 | 1 KCl | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression KI | 2 | -2 | ([KI])^(-2) HOCl | 1 | -1 | ([HOCl])^(-1) KOH | 1 | 1 | [KOH] I_2 | 1 | 1 | [I2] KCl | 1 | 1 | [KCl] 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 = ([KI])^(-2) ([HOCl])^(-1) [KOH] [I2] [KCl] = ([KOH] [I2] [KCl])/(([KI])^2 [HOCl])
Rate of reaction
Construct the rate of reaction expression for: KI + HOCl ⟶ KOH + I_2 + KCl 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: 2 KI + HOCl ⟶ KOH + I_2 + KCl 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 KI | 2 | -2 HOCl | 1 | -1 KOH | 1 | 1 I_2 | 1 | 1 KCl | 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 KI | 2 | -2 | -1/2 (Δ[KI])/(Δt) HOCl | 1 | -1 | -(Δ[HOCl])/(Δt) KOH | 1 | 1 | (Δ[KOH])/(Δt) I_2 | 1 | 1 | (Δ[I2])/(Δt) KCl | 1 | 1 | (Δ[KCl])/(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 = -1/2 (Δ[KI])/(Δt) = -(Δ[HOCl])/(Δt) = (Δ[KOH])/(Δt) = (Δ[I2])/(Δt) = (Δ[KCl])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
| potassium iodide | hypochlorous acid | potassium hydroxide | iodine | potassium chloride formula | KI | HOCl | KOH | I_2 | KCl Hill formula | IK | ClHO | HKO | I_2 | ClK name | potassium iodide | hypochlorous acid | potassium hydroxide | iodine | potassium chloride IUPAC name | potassium iodide | hypochlorous acid | potassium hydroxide | molecular iodine | potassium chloride
Substance properties
| potassium iodide | hypochlorous acid | potassium hydroxide | iodine | potassium chloride molar mass | 166.0028 g/mol | 52.46 g/mol | 56.105 g/mol | 253.80894 g/mol | 74.55 g/mol phase | solid (at STP) | | solid (at STP) | solid (at STP) | solid (at STP) melting point | 681 °C | | 406 °C | 113 °C | 770 °C boiling point | 1330 °C | | 1327 °C | 184 °C | 1420 °C density | 3.123 g/cm^3 | | 2.044 g/cm^3 | 4.94 g/cm^3 | 1.98 g/cm^3 solubility in water | | soluble | soluble | | soluble dynamic viscosity | 0.0010227 Pa s (at 732.9 °C) | | 0.001 Pa s (at 550 °C) | 0.00227 Pa s (at 116 °C) | odor | | | | | odorless
Units