Answer:
The pH of the solution is 9.43
Explanation:
sodium acetate = CH3COONa
after removing the spectator ion Na
CH3COO⁻ + H2O ⇄ CH3COOH + H3O⁺
since sodium acetate is a weak base, it will not react completely with water. Thus a value "x" will be used to make the products.
At equilibrium:
[CH3COO⁻] = 1.288 - x
[CH3COOH] = x
[H3O⁺] = x
Since a base is reacting with H2O, Kb is used at equilibrium: Kb=(1*10^-14)/(1.8*10^-5) = 5.6*10^-10)
Kb = [CH3COOH][H3O⁺]/[CH3COO⁻]
Kb = (x²)/(1.288-x) since the Kb is significantly lower than 1.288 we can make a mathematical assumption that x is significantly lower than 1.288.
5.6*10⁻¹⁰ = x²/1.288
x = [OH⁻] = 2.675*10⁻⁵ M
pOH = -log[OH⁻] = 4.57
pH=14-pOH = 14 - 4.57 = 9.43
