`(NH_(4))_(2)Cr_(2)O_(7)(` Ammonium dichromate ) is used in 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 produced when ammonium dichromate \((NH_4)_2Cr_2O_7\) is used in fireworks, we can follow these steps:

### Step 1: Identify the reaction
When ammonium dichromate is heated or blown in the air, it undergoes a decomposition reaction. The main products of this reaction are chromium(III) oxide, nitrogen gas, and water.

### Step 2: Write the balanced chemical equation
The decomposition reaction can be represented as:
\[ (NH_4)_2Cr_2O_7 \rightarrow Cr_2O_3 + N_2 + 4H_2O \]

### Step 3: Identify the green colored powder
From the balanced equation, we can see that one of the products formed is chromium(III) oxide \((Cr_2O_3)\), which is known to be green in color.

### Step 4: Conclusion
Thus, the green colored powder that is blown into the air when ammonium dichromate is used in fireworks is chromium(III) oxide \((Cr_2O_3)\).

### Final Answer
The green colored powder blown in the air is \(Cr_2O_3\) (chromium(III) oxide).

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