`K_(2)Cr_(2)O_(7) overset(Delta) to K_(2)CrO_(4)+Cr_(2)O_(3)+O_(2)uarr`

Options

A. For disproportionation reaction.
B. For comproportionation reaction.
C. For either intermolecular redox reaction or displacement reaction
D. For either thermal combination redox reaction or thermal decomposition redox reaction.

Answer

To solve the question regarding the reaction of potassium dichromate (K₂Cr₂O₇) decomposing into potassium chromate (K₂CrO₄), chromium(III) oxide (Cr₂O₃), and oxygen gas (O₂), we will analyze the type of reaction taking place.

### Step-by-Step Solution:

1. **Identify the Reactant and Products**:
- The reactant is potassium dichromate (K₂Cr₂O₇).
- The products are potassium chromate (K₂CrO₄), chromium(III) oxide (Cr₂O₃), and oxygen gas (O₂).

2. **Determine the Nature of the Reaction**:
- The reaction involves one reactant (K₂Cr₂O₇) breaking down into multiple products (K₂CrO₄, Cr₂O₃, and O₂). This indicates that the reaction is a decomposition reaction.

3. **Classify the Reaction**:
- A decomposition reaction is characterized by the breakdown of a single compound into two or more products. In this case, K₂Cr₂O₇ decomposes upon heating.
- Since this reaction also involves a change in oxidation states of chromium, it is classified as a redox reaction.

4. **Final Classification**:
- Since the reaction is a breakdown of a compound into different products and involves oxidation-reduction processes, it is specifically a **thermal decomposition redox reaction**.

### Conclusion:
The reaction of K₂Cr₂O₇ decomposing into K₂CrO₄, Cr₂O₃, and O₂ is a **thermal decomposition redox reaction**.

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