Salt Hydrolysis Notes PDF
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These notes detail salt hydrolysis, explaining the reactions of salts with water and the resulting acidic or basic solutions. It covers types of salt hydrolysis, such as salts of strong acids and strong bases, weak acids and strong bases, etc. The notes also cover the hydrolysis constant and real-world applications, such as buffer solutions, food and pharmaceuticals.
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Salt Hydrolysis - Detailed Notes Salt hydrolysis refers to the reaction of a salt with water to form an acidic or basic solution, depending on the nature of the ions present in the salt. It involves the interaction of the cation or anion of the salt with water, leading to the formation of H+ or...
Salt Hydrolysis - Detailed Notes Salt hydrolysis refers to the reaction of a salt with water to form an acidic or basic solution, depending on the nature of the ions present in the salt. It involves the interaction of the cation or anion of the salt with water, leading to the formation of H+ or OH- ions. Types of Salt Hydrolysis ------------------------- 1. Salts of Strong Acid and Strong Base: - These salts (e.g., NaCl, KNO3) do not hydrolyze because both the cation and anion are neutral and do not react with water. - Solution: Neutral (pH = 7). 2. Salts of Weak Acid and Strong Base: - Example: Sodium acetate (CH3COONa). - Hydrolysis: The anion (from the weak acid) reacts with water to produce OH- ions. - Reaction: CH3COO- + H2O -> CH3COOH + OH- - Solution: Basic (pH > 7). 3. Salts of Strong Acid and Weak Base: - Example: Ammonium chloride (NH4Cl). - Hydrolysis: The cation (from the weak base) reacts with water to produce H+ ions. - Reaction: NH4+ + H2O -> NH3 + H3O+ - Solution: Acidic (pH < 7). 4. Salts of Weak Acid and Weak Base: - Example: Ammonium acetate (CH3COONH4). - Hydrolysis: Both the cation and anion react with water. - The pH depends on the relative strengths of the weak acid and weak base. - Solution: Can be acidic, basic, or neutral. Degree of Hydrolysis -------------------- The degree of hydrolysis is the fraction of salt that undergoes hydrolysis in solution. It depends on the nature of the salt and the concentration of the solution. Hydrolysis Constant (Kh) ------------------------- Kh is the equilibrium constant for the hydrolysis reaction. For salts of weak acids and bases: - Kh = Kw / Ka (for salts of weak acids and strong bases) - Kh = Kw / Kb (for salts of strong acids and weak bases) - Kh = Kw / (Ka * Kb) (for salts of weak acids and weak bases) Applications of Salt Hydrolysis ------------------------------- 1. Buffer Solutions: Used to maintain a stable pH in chemical and biological systems. 2. Food and Pharmaceuticals: Understanding salt hydrolysis helps in the design of products with specific pH levels. 3. Water Treatment: Controlling the hydrolysis of salts helps in water purification processes.
