Question
Derive the relations:
Solution
The hydrolysis of the salt (BA) may be represented as:
Let c be the initial concentration of the salt and a be the degree of hydrolysis. At equilibrium, the concentration of various species can be represented as:
Let c be the initial concentration of the salt and a be the degree of hydrolysis. At equilibrium, the concentration of various species can be represented as:
A- + H2O
OH- + HA
Initial conc. c 0 0
Equilibrium conc.
Since
is very small as compared to unity,
From equation (2), it is clear that smaller the value of Ka (i.e. weaker the acid), the greater will be the value of a. As Kw increases with temperature, the degree of hydrolysis also increases with the increase in temperature.
A- + H2O
OH- + HAInitial conc. c 0 0
Equilibrium conc.
Since
is very small as compared to unity,From equation (2), it is clear that smaller the value of Ka (i.e. weaker the acid), the greater will be the value of a. As Kw increases with temperature, the degree of hydrolysis also increases with the increase in temperature.
