Question

8. BaSO3 would be most soluble in:

   1. 0.25 M NaOH

   2. 0.10 M AgNO3

   3. pure water

   4. 0.10 M HCl

   5. 0.25 M BaCl2

Answer 1

Correct answer is : 0.10 M HCl

Explanation

Barium sulfite BaSO₃ is made of strong base Ba(OH)₂ and weak acid sulfurous acid H₂SO₃

BaSO₃ dissociates as : BaSO₃ (s) Ba²⁺ (aq) + SO₃^2- (aq) : K = K_sp

Sulfite ion ionizes in acidic solution as : SO₃^2- (aq) + H⁺ (aq) HSO₃^- (aq) : K = 1/K_a2

bisulfite ion ionizes in acidic solution as : HSO₃^- (aq) + H⁺ (aq) H₂SO₃ (aq) : K = 1/K_a1

This process decreases the sulfite ion concentration and more BaSO₃ dissociates to fulfill this decrease.

Hence solubility of BaSO₃ increases in acidic solutions.

Among the given choices only HCl is the acidic solution.