In the wet tests for detection of various cations by precipitation , `Ba^(2+)` cations are detected by obtaining precipitate of

Options

A. `BaSO_4`
B. `BaCO_3`
C. Ba(ox): Barium oxalate
D. `Ba(OAc)_2`

Answer

To solve the problem of detecting `Ba^(2+)` cations through precipitation in wet tests, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Cation**: We need to detect the presence of barium ions, which are represented as `Ba^(2+)`.

2. **Determine the Group**: Barium belongs to Group 5 of cations in qualitative analysis. Other cations in this group include strontium and calcium.

3. **Choose the Reagent**: To precipitate barium ions, we can use ammonium carbonate (`(NH4)2CO3`). This reagent is commonly used for detecting Group 5 cations.

4. **Reaction with Ammonium Carbonate**: When we add ammonium carbonate to a solution containing barium ions, a chemical reaction occurs:
\[ Ba^{2+} + (NH_4)_2CO_3 \rightarrow BaCO_3 \downarrow + 2 NH_4^+ \]
In this reaction, barium carbonate (`BaCO3`) is formed, which is a solid precipitate.

5. **Observation of Precipitate**: The precipitate formed is barium carbonate, which is characterized by its white color. This white precipitate indicates the presence of barium ions in the solution.

6. **Conclusion**: The detection of the white precipitate of barium carbonate confirms the presence of `Ba^(2+)` cations in the solution.

### Final Answer:
Barium cations (`Ba^(2+)`) are detected by obtaining a white precipitate of **barium carbonate (BaCO3)** when ammonium carbonate is added.

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