`4K_(2) Cr_(2) O_(7) overset(heat)rarr 4K_(2) CrO_(4) + 3O_(2) + X`. In the above reaction `X` is

Options

A. `CrO_(3)`
B. `Cr_(2)O_(7)`
C. `Cr_(2)O_(3)`
D. `CrO_(5)`

Answer

To determine the value of \( X \) in the reaction:

\[ 4K_2Cr_2O_7 \xrightarrow{heat} 4K_2CrO_4 + 3O_2 + X \]

we need to analyze the decomposition of potassium dichromate (\( K_2Cr_2O_7 \)) upon heating.

### Step-by-Step Solution:

1. **Identify the Reactants and Products**:
The reactant is potassium dichromate (\( K_2Cr_2O_7 \)), and the products include potassium chromate (\( K_2CrO_4 \)), oxygen gas (\( O_2 \)), and an unknown substance \( X \).

2. **Write the Balanced Reaction**:
When potassium dichromate is heated, it decomposes to form potassium chromate and chromium oxide, along with oxygen gas. The balanced reaction can be written as:
\[ 4K_2Cr_2O_7 \rightarrow 4K_2CrO_4 + 3O_2 + X \]

3. **Determine the Composition of \( X \)**:
The decomposition of potassium dichromate typically produces chromium(III) oxide (\( Cr_2O_3 \)) as a byproduct. Therefore, we can deduce that \( X \) is \( Cr_2O_3 \).

4. **Final Balanced Reaction**:
The complete balanced equation is:
\[ 4K_2Cr_2O_7 \rightarrow 4K_2CrO_4 + 3O_2 + 2Cr_2O_3 \]
Thus, \( X = 2Cr_2O_3 \).

### Conclusion:
The value of \( X \) in the reaction is \( Cr_2O_3 \).