Ammonium dichromate is used in some fire works. The green coloured powder blown in air is

Options

A. `CrO_(3)`
B. `Cr_(2)O_(3)`
C. Cr
D. `CrO(O_(2))`

Answer

To solve the question regarding the green-colored powder blown in the air from ammonium dichromate used in fireworks, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Compound**: The compound in question is ammonium dichromate, which has the chemical formula \( \text{NH}_4\text{Cr}_2\text{O}_7 \).

2. **Understand the Reaction**: When ammonium dichromate is heated, it undergoes a decomposition reaction. The reaction can be represented as:
\[ \text{2 NH}_4\text{Cr}_2\text{O}_7 \rightarrow \text{Cr}_2\text{O}_3 + \text{N}_2 + \text{4 H}_2\text{O} \]

3. **Identify the Products**: From the balanced equation, the products formed are chromium(III) oxide (\( \text{Cr}_2\text{O}_3 \)), nitrogen gas (\( \text{N}_2 \)), and water vapor (\( \text{H}_2\text{O} \)).

4. **Determine the Color of the Product**: The chromium(III) oxide (\( \text{Cr}_2\text{O}_3 \)) produced in the reaction is known to be green in color.

5. **Conclusion**: Therefore, the green-colored powder that is blown into the air when ammonium dichromate is heated is chromium(III) oxide (\( \text{Cr}_2\text{O}_3 \)).

### Final Answer:
The green-colored powder blown in the air is \( \text{Cr}_2\text{O}_3 \) (chromium(III) oxide).

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