Determine whether aqueous solutions of the following salts are acidic, basic, or neutral: A. NaNO3 B. Na2SO4 C. (NH4)2SO4 D. K2SO4 E. K3PO4 F. KHCO3 Determine whether aqueous solutions of the following salts are acidic, basic, or neutral: A. NaNO3 B. Na2SO4 C. (NH4)2SO4 D. K2SO4 E. K3PO4 F. KHCO3
The Correct Answer and Explanation is :
To determine whether the aqueous solutions of the given salts are acidic, basic, or neutral, we need to examine the properties of their constituent ions. A salt dissolves in water to produce cations (positively charged ions) and anions (negatively charged ions). These ions may influence the solution’s pH depending on whether they are derived from strong or weak acids and bases.
Answers:
A. NaNO3: Neutral
B. Na2SO4: Neutral
C. (NH4)2SO4: Acidic
D. K2SO4: Neutral
E. K3PO4: Basic
F. KHCO3: Basic
Explanation:
- NaNO3 (Sodium Nitrate):
Sodium (Na⁺) is a spectator ion from the strong base NaOH, and nitrate (NO₃⁻) is the conjugate base of the strong acid HNO₃. Neither ion hydrolyzes in water, so the solution is neutral. - Na2SO4 (Sodium Sulfate):
Sodium (Na⁺) is from a strong base, and sulfate (SO₄²⁻) is the conjugate base of the strong acid H₂SO₄. However, since HSO₄⁻ (a weak acid) is involved in the second dissociation, the solution is effectively neutral. - (NH4)2SO4 (Ammonium Sulfate):
Ammonium (NH₄⁺) is the conjugate acid of the weak base NH₃, which hydrolyzes to release H⁺ ions, making the solution acidic. - K2SO4 (Potassium Sulfate):
Potassium (K⁺) is from the strong base KOH, and sulfate behaves as described in Na₂SO₄. Thus, the solution is neutral. - K3PO4 (Potassium Phosphate):
Potassium (K⁺) does not hydrolyze, but phosphate (PO₄³⁻) is a conjugate base of the weak acid H₃PO₄. It hydrolyzes to produce OH⁻, making the solution basic. - KHCO3 (Potassium Bicarbonate):
Potassium does not affect pH, but bicarbonate (HCO₃⁻) is a weak base (conjugate base of H₂CO₃). It hydrolyzes to produce OH⁻, so the solution is basic.
Understanding these properties allows us to predict the behavior of salts in aqueous solutions and determine their acidity, basicity, or neutrality.