What ions hydrolyze in aqueous solutions?

Question

Cameron Andrews · Accepted Answer

In aqueous solutions, two kinds of ions hydrolyze: (1) weak acid and base salts; and (2) specific metal ions.

An ion's reaction with water to create an acidic or basic solution is known as hydrolysis.

(1) Acetate ion, the conjugate base of acetic acid, hydrolyzes in water to form a basic solution, and sodium acetate is a salt of the weak acid acetic acid:

H₂O(l) + CH₃COO⁻(aq) ⇏ CH₃COOH(aq) + OH⁻(aq)

The conjugate acid of the weak base ammonia is ammonium ion, which hydrolyzes in water to form an acidic solution. Ammonium chloride is a salt of the weak base ammonia.

H₂O(l) + NH₄⁺(aq) → NH₃(aq) + H₃O⁺(aq)

(2) Metal ions are Lewis acids. In solution, they form aqua ions with the general formula #M(H₂O)_n^(m+)#. Examples are #Be(H₂O)_4^(2+)#, #Al(H₂O)_6^(3+)#, and #Fe(H₂O)_6^(3+)#. Small metal ions with high charge densities undergo hydrolysis to form acidic solutions. For example,

#Al(H₂O)_6^(3+) + H_2O ⇌ Al(H₂O)_5(OH)^(2+) + H_3O^+#

Mateo Aguilar · Answer

undefined Cations of weak bases and anions of weak acids hydrolyze in aqueous solutions.