Following types of compounds (as I, II)
`(I) CH_3 CH = CHCH_3`
`(II) CH_3 - underset(CH_2 CH_3)underset(|) CH -OH `
are studied in terms of isomerism in

Options

A. chain isomerism
B. position isomerism
C. conformers
D. stereo isomerism.

Explanation

To solve the question regarding the types of isomerism exhibited by the given compounds (I) and (II), we will analyze each compound step by step.

### Step 1: Analyze Compound I (CH₃CH=CHCH₃)
1. **Identify the structure**: The compound CH₃CH=CHCH₃ has a carbon-carbon double bond between the second and third carbon atoms.
2. **Determine the presence of different groups**: Each carbon involved in the double bond has different substituents:
- The second carbon (C2) has a methyl group (CH₃) and a hydrogen (H).
- The third carbon (C3) has a methyl group (CH₃) and a hydrogen (H).
3. **Check for restricted rotation**: The double bond restricts rotation, allowing for the possibility of geometric isomers (cis and trans forms).
4. **Conclusion**: This compound can exhibit **geometric isomerism** (cis-trans isomerism).

### Step 2: Analyze Compound II (CH₃-CH₂-CH(OH)-CH₃)
1. **Identify the structure**: The compound CH₃-CH₂-CH(OH)-CH₃ has a hydroxyl (-OH) group attached to the third carbon.
2. **Determine chirality**: The carbon that is attached to the -OH group (C3) is connected to four different groups:
- A methyl group (CH₃)
- An ethyl group (CH₂CH₃)
- A hydrogen (H)
- A hydroxyl group (OH)
3. **Check for symmetry**: Since C3 is attached to four different groups, it is a chiral center. There are no symmetry elements (like a plane of symmetry) present in this compound.
4. **Conclusion**: This compound can exhibit **optical isomerism** due to the presence of a chiral center.

### Step 3: Combine the Findings
1. **Identify the types of isomerism**:
- Compound I shows **geometric isomerism**.
- Compound II shows **optical isomerism**.
2. **Categorize the isomerism**: Both types of isomerism fall under the broader category of **stereoisomerism**.

### Final Conclusion
Both compounds (I) and (II) are studied in terms of **stereoisomerism**, which includes both geometric and optical isomerism.

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