Positive iodoform test is given by

Options

A. 1 - Pentanol
B. 3 - Pentanone
C. 2 - Pentanone
D. Pentanal

Answer

To solve the question regarding which compound gives a positive iodoform test, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Iodoform Test**: The iodoform test is a qualitative test used to identify the presence of methyl ketones (compounds with the structure R-CO-CH3) or secondary alcohols that can be oxidized to methyl ketones. A positive result is indicated by the formation of a yellow precipitate of iodoform (CHI3).

2. **Identify the Given Compounds**: The question provides us with four options:
- 1-Pentanol
- 3-Pentanone
- 2-Pentanone
- Pentanal

3. **Analyze Each Compound**:
- **1-Pentanol**: This is a primary alcohol (CH3-CH2-CH2-CH2-OH) and does not have a methyl ketone structure. Therefore, it will not give a positive iodoform test.
- **3-Pentanone**: This is a ketone (CH3-CH2-CO-CH2-CH3) but does not have a methyl group adjacent to the carbonyl carbon. Thus, it will not give a positive iodoform test.
- **2-Pentanone**: This is a methyl ketone (CH3-CO-CH2-CH2-CH3). It has the structure that allows it to react with iodine and a base to form iodoform, resulting in a positive iodoform test.
- **Pentanal**: This is an aldehyde (CH3-CH2-CH2-CHO) and does not have a methyl ketone structure. Therefore, it will not give a positive iodoform test.

4. **Conclusion**: Among the given options, only 2-Pentanone has the necessary structure to yield a positive iodoform test.

### Final Answer:
The compound that gives a positive iodoform test is **2-Pentanone**.

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