Which of the following compounds contain only `sp^3` hybridized carbon ?

Options

A. Cycloalkanes
B. Branched chain alkanes
C. Benzene
D. Cycloalkenes

Answer

To determine which of the following compounds contain only `sp^3` hybridized carbon, we need to analyze the hybridization of carbon atoms in each compound.

### Step-by-Step Solution:

1. **Understanding `sp^3` Hybridization**:
- Carbon is `sp^3` hybridized when it forms four sigma bonds. This occurs when carbon uses one `s` orbital and three `p` orbitals to form four equivalent orbitals.

2. **Analyzing Cycloalkanes**:
- Take cyclohexane as an example. Each carbon in cyclohexane forms four bonds (two with adjacent carbons and two with hydrogen atoms). Thus, all carbon atoms in cyclohexane are `sp^3` hybridized.

3. **Analyzing Branch Chain Alkanes**:
- Consider propane with a methyl branch (C3H8). Each carbon in propane forms four bonds (either with hydrogen or other carbons). Therefore, all carbons in this branched alkane are also `sp^3` hybridized.

4. **Analyzing Benzene**:
- Benzene has a structure with alternating double bonds. Each carbon in benzene forms three sigma bonds (one with another carbon and two with hydrogens) and one pi bond. Since each carbon forms only three sigma bonds, they are `sp^2` hybridized, not `sp^3`.

5. **Analyzing Cycloalkenes**:
- For cyclohexene, which contains a double bond, the two carbons involved in the double bond will be `sp^2` hybridized (forming three sigma bonds). The remaining carbons can be `sp^3` hybridized, but since not all carbons are `sp^3`, this compound does not qualify.

6. **Conclusion**:
- From the analysis, the compounds that contain only `sp^3` hybridized carbon are cyclohexane and the branched chain alkane (like propane with a methyl group).

### Final Answer:
- The compounds that contain only `sp^3` hybridized carbon are **cyclohexane and branched chain alkanes**.