CH3COOH + NaNO2 = HNO2 + CH3COONa

CH_3CO_2H acetic acid + NaNO_2 sodium nitrite ⟶ HNO_2 nitrous acid + CH_3COONa sodium acetate

Balance the chemical equation algebraically: CH_3CO_2H + NaNO_2 ⟶ HNO_2 + CH_3COONa Add stoichiometric coefficients, c_i, to the reactants and products: c_1 CH_3CO_2H + c_2 NaNO_2 ⟶ c_3 HNO_2 + c_4 CH_3COONa Set the number of atoms in the reactants equal to the number of atoms in the products for C, H, O, N and Na: C: | 2 c_1 = 2 c_4 H: | 4 c_1 = c_3 + 3 c_4 O: | 2 c_1 + 2 c_2 = 2 c_3 + 2 c_4 N: | c_2 = c_3 Na: | 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: | | CH_3CO_2H + NaNO_2 ⟶ HNO_2 + CH_3COONa

+ ⟶ +

acetic acid + sodium nitrite ⟶ nitrous acid + sodium acetate

Construct the equilibrium constant, K, expression for: CH_3CO_2H + NaNO_2 ⟶ HNO_2 + CH_3COONa 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_3CO_2H + NaNO_2 ⟶ HNO_2 + CH_3COONa 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_3CO_2H | 1 | -1 NaNO_2 | 1 | -1 HNO_2 | 1 | 1 CH_3COONa | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression CH_3CO_2H | 1 | -1 | ([CH3CO2H])^(-1) NaNO_2 | 1 | -1 | ([NaNO2])^(-1) HNO_2 | 1 | 1 | [HNO2] CH_3COONa | 1 | 1 | [CH3COONa] 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 = ([CH3CO2H])^(-1) ([NaNO2])^(-1) [HNO2] [CH3COONa] = ([HNO2] [CH3COONa])/([CH3CO2H] [NaNO2])

Construct the rate of reaction expression for: CH_3CO_2H + NaNO_2 ⟶ HNO_2 + CH_3COONa 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_3CO_2H + NaNO_2 ⟶ HNO_2 + CH_3COONa 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_3CO_2H | 1 | -1 NaNO_2 | 1 | -1 HNO_2 | 1 | 1 CH_3COONa | 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_3CO_2H | 1 | -1 | -(Δ[CH3CO2H])/(Δt) NaNO_2 | 1 | -1 | -(Δ[NaNO2])/(Δt) HNO_2 | 1 | 1 | (Δ[HNO2])/(Δt) CH_3COONa | 1 | 1 | (Δ[CH3COONa])/(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[CH3CO2H])/(Δt) = -(Δ[NaNO2])/(Δt) = (Δ[HNO2])/(Δt) = (Δ[CH3COONa])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| acetic acid | sodium nitrite | nitrous acid | sodium acetate formula | CH_3CO_2H | NaNO_2 | HNO_2 | CH_3COONa Hill formula | C_2H_4O_2 | NNaO_2 | HNO_2 | C_2H_3NaO_2 name | acetic acid | sodium nitrite | nitrous acid | sodium acetate

| acetic acid | sodium nitrite | nitrous acid | sodium acetate molar mass | 60.052 g/mol | 68.995 g/mol | 47.013 g/mol | 82.034 g/mol phase | liquid (at STP) | solid (at STP) | | solid (at STP) melting point | 16.2 °C | 271 °C | | 300 °C boiling point | 117.5 °C | | | 881.4 °C density | 1.049 g/cm^3 | 2.168 g/cm^3 | | 1.528 g/cm^3 solubility in water | miscible | | | soluble surface tension | 0.0288 N/m | | | dynamic viscosity | 0.001056 Pa s (at 25 °C) | | | odor | vinegar-like | | | odorless