Question

An unknown acid solution was presumed to be either $HCl$ or H${}_2$SO${}_4$. Which one of the following salt solutions would produce a precipitate when added to H${}_2$SO${}_4$ but not when added to $HCl$?

• A. LiNO${}_3$
• B. NH${}_4$NO${}_3$
• C. CsNO${}_3$
• D. Ba(NO${}_3$)${}_2$
• E. AgNO${}_3$

Answer 1

The correct option is D Ba(NO${}_3$)${}_2$

When a solution of barium salt is added to $H_{2}S{O}_4$, barium sulphate is formed. Since the solubility of sulphates decrease across a group, it forms a precipitate. However Barium salts produce $BaC{l}_2$ when added to $HCl$ which is soluble and hence no precipitate is formed