`C_(5)H_(12)O` is a monohydric alcohol . How many isomers of this alcohol are possible ? How many of these contain chiral centres as well as can exhibit enantiomerism ?

Options

A. 8 and 3
B. 6 and 2
C. 4 and 2
D. 12 and 4

Explanation

To determine the number of isomers for the monohydric alcohol with the formula \( C_5H_{12}O \) and to identify how many of these isomers contain chiral centers and can exhibit enantiomerism, we can follow these steps:

### Step 1: Identify the structure of the alcohol
The molecular formula \( C_5H_{12}O \) indicates that we have 5 carbon atoms, 12 hydrogen atoms, and one hydroxyl group (-OH) characteristic of alcohols.

### Step 2: Determine possible structural isomers
We can have different structural isomers based on the position of the hydroxyl group and the arrangement of carbon atoms (straight-chain and branched). The possible isomers include:

1. **Pentanol (1-pentanol)**: \( CH_3(CH_2)_4OH \)
2. **2-Pentanol**: \( CH_3CH(OH)CH_2CH_2CH_3 \)
3. **3-Pentanol**: \( CH_3CH_2CH(OH)CH_2CH_3 \)
4. **2-Methyl-1-butanol**: \( CH_3CH(OH)CH_2CH_3CH_3 \)
5. **3-Methyl-1-butanol**: \( CH_3CH_2CH(OH)CH_3CH_3 \)
6. **2-Methyl-2-butanol**: \( (CH_3)_2C(OH)(CH_2)CH_3 \)
7. **3-Methyl-2-butanol**: \( CH_3CH(OH)(CH_3)CH_2CH_3 \)
8. **2,2-Dimethyl-1-propanol**: \( (CH_3)_3C(OH) \)

### Step 3: Count the total number of isomers
From the above analysis, we can see that there are **8 possible structural isomers** for \( C_5H_{12}O \).

### Step 4: Identify chiral centers
A chiral center is typically a carbon atom that is bonded to four different groups. We will analyze each isomer:

1. **1-Pentanol**: No chiral center.
2. **2-Pentanol**: Chiral center at C-2 (can exhibit enantiomerism).
3. **3-Pentanol**: Chiral center at C-3 (can exhibit enantiomerism).
4. **2-Methyl-1-butanol**: No chiral center.
5. **3-Methyl-1-butanol**: No chiral center.
6. **2-Methyl-2-butanol**: Chiral center at C-2 (can exhibit enantiomerism).
7. **3-Methyl-2-butanol**: Chiral center at C-3 (can exhibit enantiomerism).
8. **2,2-Dimethyl-1-propanol**: No chiral center.

### Step 5: Count the isomers with chiral centers
From the analysis, the isomers that contain chiral centers and can exhibit enantiomerism are:
- 2-Pentanol
- 3-Pentanol
- 2-Methyl-2-butanol
- 3-Methyl-2-butanol

Thus, there are **4 isomers** that can exhibit enantiomerism.

### Final Answer
- Total number of isomers: **8**
- Number of isomers with chiral centers that can exhibit enantiomerism: **4**

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