`Se_(2)Cl_(2)overset(Delta)toSeCl_(4)+Se`

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 determine the type of reaction for the given equation \( \text{Se}_2\text{Cl}_2 \overset{\Delta}{\rightarrow} \text{SeCl}_4 + \text{Se} \), we will analyze the oxidation states of selenium (Se) in the reactants and products.

### Step-by-Step Solution:

1. **Identify the Reactants and Products**:
- Reactant: \( \text{Se}_2\text{Cl}_2 \)
- Products: \( \text{SeCl}_4 \) and \( \text{Se} \)

2. **Determine the Oxidation State of Selenium in the Reactant**:
- The formula for \( \text{Se}_2\text{Cl}_2 \) indicates there are 2 selenium atoms and 2 chlorine atoms.
- Let the oxidation state of Se be \( x \).
- The equation for the oxidation states can be set up as:
\[ 2x + 2(-1) = 0 \]
- This simplifies to:
\[ 2x - 2 = 0 \implies 2x = 2 \implies x = +1 \]
- Therefore, the oxidation state of Se in \( \text{Se}_2\text{Cl}_2 \) is +1.

3. **Determine the Oxidation State of Selenium in the Products**:
- In \( \text{SeCl}_4 \):
- Let the oxidation state of Se be \( y \).
- The equation for the oxidation states can be set up as:
\[ y + 4(-1) = 0 \]
This simplifies to:
\[ y - 4 = 0 \implies y = +4 \]
- In elemental Se (the product Se), the oxidation state is 0.

4. **Analyze the Changes in Oxidation States**:
- In \( \text{Se}_2\text{Cl}_2 \), Se has an oxidation state of +1.
- In \( \text{SeCl}_4 \), Se has an oxidation state of +4 (oxidation).
- In elemental Se, Se has an oxidation state of 0 (reduction).

5. **Determine the Type of Reaction**:
- Since one species (Se) is being oxidized from +1 to +4 and another species (Se) is being reduced from +1 to 0, this indicates that the same element (Se) is undergoing both oxidation and reduction.
- This is characteristic of a **disproportionation reaction**.

6. **Consider the Thermal Aspect**:
- The reaction is initiated by heat (indicated by \( \Delta \)), which suggests that it is also a **thermal decomposition** reaction, as the reactant decomposes into two products.

### Conclusion:
The reaction \( \text{Se}_2\text{Cl}_2 \overset{\Delta}{\rightarrow} \text{SeCl}_4 + \text{Se} \) is both a **disproportionation reaction** and a **thermal decomposition redox reaction**.