Pentan -2- one differs from pentane-3 one in that :

Options

A. Pentane-2-one does not give iodoform test
B. Pentane-2-one gives iodoform test
C. Pentane-3-one gives iodoform test
D. Pentane-2-one does not react with `NaHSO_(3)`

Answer

To determine the difference between Pentan-2-one and Pentan-3-one, we need to analyze their structures and the tests they undergo.

### Step 1: Identify the structures of Pentan-2-one and Pentan-3-one.
- **Pentan-2-one** has the carbonyl group (C=O) on the second carbon of the pentane chain. Its structure can be represented as:
```
CH3-CH2-C(=O)-CH2-CH3
```
- **Pentan-3-one** has the carbonyl group on the third carbon. Its structure is:
```
CH3-CH2-CH(=O)-CH2-CH3
```

### Step 2: Analyze the Iodoform test.
The Iodoform test is a qualitative test for the presence of methyl ketones (ketones with the structure R-CO-CH3).

- **Pentan-2-one** does not have a methyl group (CH3) adjacent to the carbonyl carbon (C=O). Therefore, it will **not** give a positive Iodoform test.

- **Pentan-3-one** has a methyl group adjacent to the carbonyl carbon (C=O). Thus, it will give a **positive Iodoform test**.

### Step 3: Reactivity with Sodium Bisulfite (NaHSO3).
- **Pentan-2-one** can react with sodium bisulfite to form a bisulfite adduct, indicating the presence of a ketone.

- **Pentan-3-one** will also react with sodium bisulfite to form a similar adduct.

### Conclusion:
The main difference between Pentan-2-one and Pentan-3-one is that **Pentan-3-one gives a positive Iodoform test**, while **Pentan-2-one does not**.

### Final Answer:
Pentan-2-one differs from Pentan-3-one in that Pentan-3-one gives a positive Iodoform test, whereas Pentan-2-one does not.

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