Hello!
The compound that will form an acidic solution when dissolved in water is KHSO₄.
An acidic solution is one with a pH between 0-7. For it to be in this pH range, the solution needs to have hydronium ions (H₃O⁺). KHSO₄ generates these ions by the following dissociation reactions:
KHSO₄(s) →K⁺(aq) + HSO₄⁻ (aq)
HSO₄⁻(aq) + H₂O → H₃O⁺(aq) + SO₄⁻²(aq)
As the solution has hydronium ions, it will be an acidic solution.
