Answer :

Answer:

The correct option is;

a. BaSO4.

Explanation:

a. BaSO₄ Insoluble

From the solubility table, we have all sulfates SO₄ are soluble except those of Sr²⁺, Ag⁺, Ca²⁺ ,Pb²⁺ Ba²⁺,  Hg²⁺

b. KNO₃ Soluble

All nitrates are soluble, no exceptions

c. Na₂SO₄ Soluble

Sodium sulfate is among the soluble sulfates.

d. Li₂CO₃ Soluble

All carbonates are insoluble except those of NH₄⁺ and group IA.