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 when heated with Zn dust in ethanol, we can follow these steps:

### Step 1: Understand the Reactants
1,2-Dibromopropane has the following structural formula:
- CH3-CHBr-CH2Br

This means that there are two bromine atoms attached to the second and third carbon atoms of a three-carbon propane chain.

### Step 2: Identify the Reaction Type
When 1,2-dibromopropane is heated with zinc dust in ethanol, we are looking at a dehalogenation reaction. Zinc acts as a reducing agent, which helps in the removal of halogen atoms (bromine in this case) from the organic molecule.

### Step 3: Write the Reaction
The reaction can be represented as follows:
- 1,2-dibromopropane + Zn → Propene + ZnBr2

The bromine atoms are removed, resulting in the formation of a double bond between the first and second carbon atoms, leading to the formation of propene.

### Step 4: Determine the Product
The product formed from the dehalogenation of 1,2-dibromopropane is propene (C3H6), which has the structure:
- CH2=CH-CH3

### Conclusion
Thus, the final answer to the question is that 1,2-dibromopropane when heated with Zn dust in ethanol gives **propene**.