When aqueous solutions of two salts are mixed, the third salt formed may appear as a solid precipitates or a clear solution depending upon the solubility of its ions. It is observed that all salts of $\mathrm{Na}, \mathrm{K}, \mathrm{NH}_4$ are soluble. All nitrates and bicarbonates are also soluble. All halides (chlorides, bromides, iodides) are soluble except those of $\mathrm{Ag}, \mathrm{Hg}$ (I) and Pb . All sulphates are soluble except those of $\mathrm{Ag}, \mathrm{Ca}, \mathrm{Ba}$ and Pb . Which one among the following combinations of solutions will produce a solid precipitate?

• A

  Sodium sulphate and barium chloride
• Correct answer
  B

  Magnesium sulphate and barium bicarbonate
• C

  Lithium iodide and barium chloride
• D

  Ammonium sulphate and potassium bromide

Hence, the correct answer is option: 'B'.