Chromyl chloride vapours are dissolved in water and acetic acid and barium acetate solution is added then:

Options

A. the solution will remain colourless
B. the solution will become dark green
C. a yellow solution will be obtained
D. a yellow precipitate will be obtained

Explanation

To solve the question regarding the reaction of chromyl chloride vapors with water, acetic acid, and barium acetate, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Chemical Species**:
- Chromyl chloride is represented as CrO2Cl2. When it is in vapor form and is dissolved in water (H2O), it will undergo hydrolysis.

2. **Hydrolysis of Chromyl Chloride**:
- The reaction of chromyl chloride with water can be written as:
\[ \text{CrO}_2\text{Cl}_2 + 2 \text{H}_2\text{O} \rightarrow \text{H}_2\text{CrO}_4 + 2 \text{HCl} \]
- This means that chromyl chloride reacts with water to produce chromic acid (H2CrO4) and hydrochloric acid (HCl).

3. **Addition of Acetic Acid and Barium Acetate**:
- Next, we add acetic acid (CH3COOH) and barium acetate (Ba(CH3COO)2) to the solution containing chromic acid.
- In an acidic medium, barium acetate will react with chromic acid to form barium chromate (BaCrO4) and acetic acid:
\[ \text{H}_2\text{CrO}_4 + \text{Ba(CH}_3\text{COO)}_2 \rightarrow \text{BaCrO}_4 \downarrow + 2 \text{CH}_3\text{COOH} \]

4. **Formation of Precipitate**:
- Barium chromate (BaCrO4) is a yellow precipitate. Therefore, when barium acetate is added to the solution, a yellow precipitate of barium chromate will form.

5. **Conclusion**:
- The final observation is that a yellow precipitate of barium chromate will be obtained upon the addition of barium acetate to the solution containing chromic acid.

### Final Answer:
The yellow precipitate of barium chromate (BaCrO4) will form when barium acetate is added to the solution.