Which is maximum soluble in water?

Options

A. n-butyl alcohol
B. Isobutyl alcohol
C. ter-butyl alcohol
D. Sec-butyl alchohol

Explanation

To determine which alcohol is the most soluble in water, we can analyze the structures and properties of the given alcohols: n-butyl alcohol, isobutyl alcohol, tertiary butyl alcohol, and secondary butyl alcohol.

### Step-by-Step Solution:

1. **Identify the Structures of the Alcohols**:
- **n-Butyl Alcohol**: This is a straight-chain alcohol with the formula CH3-CH2-CH2-CH2-OH.
- **Isobutyl Alcohol**: This is a branched-chain alcohol with the formula (CH3)2CH-CH2-OH.
- **Tertiary Butyl Alcohol**: This is a highly branched alcohol with the formula (CH3)3C-OH.
- **Secondary Butyl Alcohol**: This is another branched alcohol with the formula CH3-CH(OH)-CH2-CH3.

2. **Understand the Concept of Solubility**:
- Alcohols are generally soluble in water due to the presence of the hydroxyl (-OH) group, which can form hydrogen bonds with water molecules.
- The solubility of alcohols in water is influenced by the size of the alkyl group and the degree of branching.

3. **Analyze the Effect of Alkyl Chain Length**:
- As the length of the alkyl chain increases, the solubility in water decreases. This is because longer alkyl chains are hydrophobic and do not interact favorably with water.

4. **Consider the Effect of Branching**:
- More branching in the alkyl chain generally increases solubility. This is because branching reduces the hydrophobic surface area, allowing for more effective hydrogen bonding with water.

5. **Compare the Alcohols**:
- **n-Butyl Alcohol**: Least branched, longer chain, lower solubility.
- **Isobutyl Alcohol**: More branched than n-butyl but less than tertiary butyl, moderate solubility.
- **Tertiary Butyl Alcohol**: Highly branched, smallest hydrophobic surface area, highest solubility.
- **Secondary Butyl Alcohol**: Less branched than tertiary butyl but more than n-butyl, moderate solubility.

6. **Conclusion**:
- Based on the analysis, **tertiary butyl alcohol** is the most soluble in water due to its high degree of branching, which allows for effective hydrogen bonding with water.

### Final Answer:
**Tertiary butyl alcohol is the most soluble in water.**