1, 2 - dibromopropane , when heated with Zn dust in ethanol, gives

Options

A. propane
B. propene
C. propene
D. ethyne

Answer

To solve the question regarding the reaction of 1,2-dibromopropane with zinc dust in ethanol, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure of 1,2-Dibromopropane**:
- 1,2-dibromopropane has the following structure:
```
CH3-CHBr-CH2Br
```
- This means there are three carbon atoms (propane) with bromine atoms attached to the first and second carbon.

2. **Understand the Reaction Conditions**:
- The reaction involves heating 1,2-dibromopropane with zinc dust in ethanol. Zinc dust is a reducing agent, and ethanol acts as a solvent.

3. **Recognize the Type of Reaction**:
- The reaction is a **dehalogenation reaction**. In this process, the bromine atoms attached to adjacent carbon atoms will be removed.

4. **Mechanism of Dehalogenation**:
- When heated with zinc dust, the bromine atoms on the adjacent carbons (C1 and C2) will be eliminated, resulting in the formation of a double bond between these two carbons.
- The reaction can be summarized as:
```
CH3-CHBr-CH2Br + Zn → CH3-CH=CH2 + ZnBr2
```
- Here, ZnBr2 is formed as a byproduct.

5. **Determine the Product**:
- The resulting compound after the elimination of bromine is propene (CH3-CH=CH2).
- The IUPAC name for this compound is **prop-1-ene** because the double bond is located between the first and second carbon atoms.

6. **Final Answer**:
- Therefore, the product obtained from the reaction of 1,2-dibromopropane with zinc dust in ethanol is **prop-1-ene**.