Among these chain isomers are :
(I) `CH_(3)-CH_(3)-CH_(2)-CH_(2)-OH`
(II) `CH_(3)-CH_(2)-underset(OH)underset(|)(CH)-CH_(3)`
(III) `CH_(3)-underset(CH_(3))underset(|)overset(OH)overset(|)(C)-CH_(3)`

Options

A. I only
B. I and III
C. I and II
D. None of these

Answer

To determine which of the given compounds are chain isomers, we need to analyze the structures of each compound and see if they have the same molecular formula but different arrangements of the carbon skeleton.

### Step 1: Identify the molecular formulas of each compound.

1. **Compound I**: `CH₃-CH₂-CH₂-CH₂-OH`
- This compound has 4 carbon atoms (C) and 10 hydrogen atoms (H) along with one oxygen atom (O).
- Molecular formula: C₄H₁₀O

2. **Compound II**: `CH₃-CH-CH₂-CH₃` with an OH group on the second carbon.
- This compound also has 4 carbon atoms and 10 hydrogen atoms, with one oxygen atom.
- Molecular formula: C₄H₁₀O

3. **Compound III**: `CH₃-C(CH₃)-OH` with a methyl group on the second carbon.
- This compound has 5 carbon atoms and 12 hydrogen atoms, with one oxygen atom.
- Molecular formula: C₅H₁₂O

### Step 2: Compare the molecular formulas.

- **Compound I**: C₄H₁₀O
- **Compound II**: C₄H₁₀O
- **Compound III**: C₅H₁₂O

### Step 3: Identify chain isomers.

Chain isomers have the same molecular formula but different arrangements of carbon atoms.

- **Compound I and Compound II** both have the same molecular formula (C₄H₁₀O) and different arrangements of carbon atoms, making them chain isomers.
- **Compound III** has a different molecular formula (C₅H₁₂O) compared to Compounds I and II, so it cannot be a chain isomer with them.

### Conclusion:

The chain isomers among the given compounds are **Compound I (C₄H₁₀O)** and **Compound II (C₄H₁₀O)**.

### Final Answer:

The chain isomers are: **(I) and (II)**.

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