A salt of strong acid and a weak base is dissolved in water....

A salt of strong acid and a weak base is dissolved in water. Its hydrolysis in solution is
(a) not affected by heating
(b) increased by adding the strong acid
(c) suppressed by adding strong acid
(d) suppressed by dilution

Key Concepts

Acid-Base Hydrolysis

Acid-base hydrolysis refers to the reaction of ions from a salt with water to produce either hydronium or hydroxide ions, thereby making the solution acidic or basic. In the case of a salt derived from a strong acid and a weak base, the conjugate acid of the weak base reacts with water to produce hydronium ions, resulting in an acidic solution.

Salt Hydrolysis Equilibrium

This concept involves the dynamic equilibrium established when the ion from the weak base undergoes hydrolysis in water. The equilibrium can be influenced by the addition of other acids or bases, which affect the concentration of the ions involved and thus shift the equilibrium position.

Le Chatelier's Principle

Le Chatelier's Principle provides insight into how a chemical equilibrium responds to external changes such as concentration, temperature, or pressure. It explains that if a system at equilibrium is disturbed, the system will shift in the direction that minimizes the disturbance. This principle is key in understanding the suppression or enhancement of salt hydrolysis when an external reagent is added.

Effect of Adding a Strong Acid

When a strong acid is added to a solution containing the conjugate acid of a weak base, it increases the concentration of the common ion (such as hydronium ion), which according to Le Chatelier's Principle, shifts the equilibrium to the left, thereby suppressing further hydrolysis.

Effect of Dilution

Dilution generally decreases the concentrations of all dissolved species, which can shift the equilibrium position in response. However, in the context of salt hydrolysis, dilution may reduce the extent of hydrolysis by lowering the ion concentrations, but it does not suppress the reaction in the same way as the addition of a common ion like a strong acid.

Temperature Effects on Equilibrium

Temperature changes can affect the equilibrium constants of reactions according to the van 't Hoff equation. However, for certain equilibria such as salt hydrolysis, if the enthalpy change is small, the effect of temperature may be minimal, meaning that heating might not significantly alter the degree of hydrolysis.

Transcript

Please give Ace some feedback