Potassium chromate solution is added to an aqueous solution of a metal chlrodie. The precipitate thus obtained are insoluble in acetic acid. These are subjected to flame test, the colour of the flame is

Options

A. Lilac
B. Apple green
C. Crimson red
D. Blue

Explanation

To solve the question step by step, we need to analyze the information given about potassium chromate and the metal chloride solution.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
When potassium chromate (K2CrO4) is added to an aqueous solution of a metal chloride (MCl), a precipitate is formed. The chromate ion (CrO4^2-) can react with certain metal ions to form insoluble chromates.

2. **Identifying the Metals**:
The metals that typically form insoluble chromates include lead (Pb^2+) and barium (Ba^2+). Both of these metals will react with chromate ions to form yellow precipitates of lead chromate (PbCrO4) and barium chromate (BaCrO4).

3. **Solubility in Acetic Acid**:
The problem states that the precipitate is insoluble in acetic acid (CH3COOH). This is an important clue because it confirms the presence of either lead or barium, as both of these chromates are indeed insoluble in acetic acid.

4. **Flame Test**:
Next, we perform a flame test on the precipitate. The flame test is a qualitative analysis technique used to identify the presence of certain metal ions based on the color they emit when heated in a flame.
- Barium (Ba^2+) produces an apple green flame.
- Lead (Pb^2+) does not produce a distinct flame color that is easily identifiable.

5. **Conclusion**:
Since the precipitate is confirmed to be insoluble in acetic acid and the flame test is being conducted, we can conclude that the metal ion present is likely barium (Ba^2+), which gives an apple green color in the flame test.

### Final Answer:
The color of the flame is **apple green**.

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