Question

The percentage degree of hydrolysis of a salt of weak acid (HA) and the weak base (BOH) in its 0.1M solution is found to be 10 percent. If the molarity of the solution is 0.05M, the percentage hydrolysis of the salt should be:
(A) $5%$
(B) $10%$
(C) $20%$
(D) None of the above

Answer 1

Hint: Degree of hydrolysis is the cleavage of peptide bonds in the protein hydrolysate. Degree of dissociation is the phenomenon in which free ions are generated which carries current, which are dissociated from the fraction of solute at a given concentration. The degree of dissociation for strong acid and base is equal to 1 because they completely dissociate in water.

Complete step by step solution:
When both acid and base are weak, then neither of them dissociate completely so neutralization reaction does not take place. They remain in equilibrium which is a state in when the rate of formation of reactant is equal to the rate of formation of product.
The degree of hydrolysis of salt of weak acid and weak base is independent of the concentration i.e. molarity of the solution.
Given in the question:
Degree of hydrolysis of a salt of weak acid (HA) and the weak base (BOH) in its 0.1M solution = 10$%$.
The degree of hydrolysis for the salt of weak acid and weak base is given by the expression =
\[{{K}_{h}}=\dfrac{{{K}_{w}}}{{{K}_{a}}{{K}_{b}}}\]
Where ${{K}_{h}}$= is the degree of dissociation
${{K}_{\begin{smallmatrix}
 w \\

\end{smallmatrix}}}$= the ionic product of water
${{K}_{a}}$ = acid dissociation constant
${{K}_{b}}$ = base dissociation constant
This expression shows that the degree of hydrolysis of salt of weak acid and weak base is independent of the concentration.

Hence, if the molarity of the solution is 0.05M the percentage hydrolysis of the salt is 10$%$.

Note: Weak acid is an acid which dissociates partially into its ions in water or in an aqueous solution. Similarly weak base is a base which dissociates partially into its ions in water or in an aqueous solution. The ionization reaction in both weak acid and weak base is irreversible.