1. what ion in NaC2H3O2 hydrolyzed?
2.what would be equation showing the ion reacting in water?
The Correct Answer and Explanation is :
Hydrolyzed Ion in NaC₂H₃O₂ and Hydrolysis Equation
- The hydrolyzed ion in sodium acetate (NaC₂H₃O₂)
- Sodium acetate (NaC₂H₃O₂) is a salt composed of sodium ions (Na⁺) and acetate ions (C₂H₃O₂⁻).
- The sodium ion (Na⁺) comes from a strong base (NaOH), while the acetate ion (C₂H₃O₂⁻) comes from a weak acid (acetic acid, HC₂H₃O₂).
- Since acetic acid is weak, the acetate ion (C₂H₃O₂⁻) undergoes hydrolysis in water, making it the hydrolyzed ion.
- Hydrolysis equation of the acetate ion in water: C2H3O2−+H2O⇌HC2H3O2+OH−\text{C}_2\text{H}_3\text{O}_2^- + \text{H}_2\text{O} \rightleftharpoons \text{HC}_2\text{H}_3\text{O}_2 + \text{OH}^-
Explanation of the Hydrolysis Reaction (300 Words)
When sodium acetate (NaC₂H₃O₂) dissolves in water, it dissociates completely into Na⁺ and C₂H₃O₂⁻. The sodium ion (Na⁺) does not hydrolyze because it comes from a strong base (NaOH) and has no affinity for protons. However, the acetate ion (C₂H₃O₂⁻) is the conjugate base of acetic acid (HC₂H₃O₂), which is a weak acid. This means that acetate has a tendency to react with water to form acetic acid and hydroxide ions (OH⁻).
This reaction increases the concentration of hydroxide ions (OH⁻) in solution, making the solution slightly basic. This is why aqueous sodium acetate solutions have a pH greater than 7. The extent of this hydrolysis depends on the base dissociation constant (Kb) of acetate, which can be calculated using the relationship: Kb=KwKaK_b = \frac{K_w}{K_a}
where KwK_w is the ionization constant of water (1.0 × 10⁻¹⁴) and KaK_a is the acid dissociation constant of acetic acid (1.8 × 10⁻⁵). This results in a weak base, explaining why sodium acetate solutions are slightly basic.
Understanding this hydrolysis process is crucial in buffer solutions, where sodium acetate and acetic acid work together to maintain pH stability. This principle is widely used in biochemical applications, pharmaceuticals, and laboratory settings where pH control is essential.