Question

In general tests of Ba$^{2+}$ and Ca$^{2+}$ give the respective tests as:

• A. Chromate, Sulphate
• B. Sulphite, Sulphate
• C. Hydroxide, Carbonate
• D. Carbonate, Carbonate

Hint:

Group IV cations give carbonate precipitates with ammonium carbonate.

Answer 1

The Correct Option is D

The question asks about the general tests for the presence of barium ions (Ba²⁺) and calcium ions (Ca²⁺), specifically the type of reagents that form precipitates with these ions.

1. Understanding the Chemical Reactions:
   • Barium ions (Ba²⁺) typically form a precipitate when treated with certain anions, often used as tests to identify their presence.
   • Calcium ions (Ca²⁺) also form precipitates with specific anions, which serve as a means of identification.
2. Reactions:
   • Ba^{2+}\: \text{reacts with} \: CO_3^{2-} \, \rightarrow \, \text{BaCO}_3 \, (\text{Barium carbonate, a white precipitate})
   • Ca^{2+}\: \text{reacts with} \: CO_3^{2-} \, \rightarrow \, \text{CaCO}_3 \, (\text{Calcium carbonate, a white precipitate})
3. Reasoning:
   • Barium and calcium ions both form insoluble carbonates when mixed with carbonate ions (CO₃^2-), leading to the formation of a white precipitate.
   • This reaction is characteristic and is employed as a qualitative analysis technique to identify these ions in a mixture.
4. Conclusion:
   • The correct option is "Carbonate, Carbonate" since both barium and calcium form carbonates in their respective tests.