A salt having `BO_(3)^(3-)` on burning with conc `H_(2)SO_(4)` gives …. edged flame.

Options

A. Green
B. yellow
C. Red
D. White

Explanation

To solve the question regarding the color of the flame produced when a salt containing the borate ion \( \text{BO}_3^{3-} \) is burned with concentrated \( \text{H}_2\text{SO}_4 \), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reaction**:
When a borate salt (for example, sodium borate \( \text{Na}_3\text{BO}_3 \)) reacts with concentrated sulfuric acid \( \text{H}_2\text{SO}_4 \), it produces sodium sulfate \( \text{Na}_2\text{SO}_4 \) and boric acid \( \text{H}_3\text{BO}_3 \).

\[ \text{Na}_3\text{BO}_3 + \text{H}_2\text{SO}_4 \rightarrow \text{Na}_2\text{SO}_4 + \text{H}_3\text{BO}_3 \]

2. **Balance the Reaction**:
The balanced equation for the reaction would be:

\[ 2 \text{Na}_3\text{BO}_3 + 3 \text{H}_2\text{SO}_4 \rightarrow 3 \text{Na}_2\text{SO}_4 + 2 \text{H}_3\text{BO}_3 \]

3. **Boric Acid Reaction with Alcohol**:
The boric acid \( \text{H}_3\text{BO}_3 \) reacts with an alcohol (e.g., ethanol \( \text{C}_2\text{H}_5\text{OH} \)) to form a tri-alkyl borate, which is flammable.

\[ \text{H}_3\text{BO}_3 + 3 \text{C}_2\text{H}_5\text{OH} \rightarrow \text{C}_2\text{H}_5\text{BO}_3 + 3 \text{H}_2\text{O} \]

4. **Flame Color Observation**:
When the tri-alkyl borate burns, it produces a characteristic green etched flame. This is a well-known property of boron compounds when they are burned.

5. **Conclusion**:
Therefore, the flame produced when a salt containing the borate ion \( \text{BO}_3^{3-} \) is burned with concentrated sulfuric acid is a **green etched flame**.

### Final Answer:
The salt having \( \text{BO}_3^{3-} \) on burning with concentrated \( \text{H}_2\text{SO}_4 \) gives a **green etched flame**.

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