Which of the following is unsaturated hydrocarbon?

Options

A.
B.
C.
D.

Answer

To determine which of the given compounds is an unsaturated hydrocarbon, we need to follow these steps:

### Step 1: Understand Unsaturated Hydrocarbons
Unsaturated hydrocarbons are compounds that contain at least one double bond (alkenes) or triple bond (alkynes) between carbon atoms. These bonds allow the compounds to undergo addition reactions.

### Step 2: Analyze Each Compound
We will examine each option provided in the question to identify if it contains double or triple bonds.

1. **Cycloalkane**: Cycloalkanes are saturated hydrocarbons because they only contain single bonds. Therefore, this option is not an unsaturated hydrocarbon.

2. **Alkene**: If this compound contains a double bond, it is classified as an unsaturated hydrocarbon. This compound can undergo addition reactions due to the presence of the double bond.

3. **Ketone**: Ketones have a carbonyl group (C=O), which is not a carbon-carbon double bond. However, they can still undergo addition reactions, making them unsaturated in a broader sense.

4. **Diene**: A diene contains two double bonds, which makes it an unsaturated hydrocarbon. It can also undergo addition reactions due to the presence of these double bonds.

### Step 3: Conclusion
Based on the analysis:
- The cycloalkane is saturated.
- The alkene (option 2) is unsaturated.
- The ketone (option 3) is considered unsaturated due to its ability to undergo addition reactions.
- The diene (option 4) is also unsaturated.

Thus, the unsaturated hydrocarbons among the options are **option 2, option 3, and option 4**.

### Final Answer
**Options 2, 3, and 4 are unsaturated hydrocarbons.**

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