Which of the following is the green coloured powder produced when ammonium dichromate is used in fire works

Options

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

Explanation

To determine which green-colored powder is produced when ammonium dichromate is used in fireworks, we can follow these steps:

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

### Step 2: Understand the Reaction
When ammonium dichromate is heated, it undergoes a decomposition reaction. The products of this reaction include chromium(III) oxide, nitrogen gas, and water. The balanced equation for this reaction can be written as:
\[ \text{NH}_4\text{Cr}_2\text{O}_7 \rightarrow \text{Cr}_2\text{O}_3 + \text{N}_2 + 4\text{H}_2\text{O} \]

### Step 3: Identify the Color of the Product
Among the products formed, we need to identify the color of chromium(III) oxide (\( \text{Cr}_2\text{O}_3 \)). It is known that chromium(III) oxide is a green-colored powder.

### Step 4: Compare with Given Options
Now, let's compare the product \( \text{Cr}_2\text{O}_3 \) with the options provided:
1. Chromium (Cr) - This is a metal and does not exist as a powder.
2. \( \text{CrO}_3 \) - This is chromium trioxide, which is not green.
3. \( \text{Cr}_2\text{O}_3 \) - This is chromium(III) oxide, which is green.
4. \( \text{CrO}_2 \) - This is chromium(II) oxide, which is also not green.

### Conclusion
The green-colored powder produced when ammonium dichromate is used in fireworks is \( \text{Cr}_2\text{O}_3 \).

### Final Answer
**The correct answer is \( \text{Cr}_2\text{O}_3 \).**

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