Question

Calculate 

• the hydrolysis constant, 
• degree of hydrolysis and 
• pH of O.1 M CH₃COONa solution (pK_a for CH₃COOH is 4.74).

Answer 1

CH₃COONa is a salt of weak acid (CH₃COOH) and a strong base (NaOH). Hence, the solutions is alkaline due to hydrolysis.

CH₃COO (aq) + H₂O (aq) ⇌ CH₃COOH (aq) + OH^- (aq)

Give that pK_a = 4.74

pK_a = – log K_a 

i.e., K_a = antilog of ( – PK_a) 

= antilog of ( – 4.74) 

= antilog of( – 5 + 0.26) 

= 1.8 x 10^-5