Which one of the following compounds will give orange precipitate when treated with 2,4- dinitrophenyl hydrazine ?

Options

A.
B.
C.
D.

Answer

To determine which compound will give an orange precipitate when treated with 2,4-dinitrophenylhydrazine (2,4-DNP), we need to understand the nature of the reaction and the types of compounds that react with 2,4-DNP.

### Step-by-Step Solution:

1. **Understanding 2,4-DNP**:
- 2,4-Dinitrophenylhydrazine is a reagent used to test for the presence of carbonyl groups (C=O) in aldehydes and ketones. It forms a hydrazone derivative with these compounds, which typically precipitates out as a colored solid.

2. **Identifying Carbonyl Compounds**:
- The compounds that will react with 2,4-DNP to give an orange precipitate must contain a carbonyl group, specifically aldehydes or ketones. Esters and carboxylic acids do not typically react to form a precipitate with 2,4-DNP.

3. **Analyzing the Options**:
- We need to evaluate each of the given options to identify which one contains a carbonyl group that can react with 2,4-DNP:
- **Option 1**: Contains a ketone group (R-C(=O)-R').
- **Option 2**: Contains an ester group (R-C(=O)-O-R').
- **Option 3**: Contains a carboxylic acid group (R-C(=O)-OH).
- **Option 4**: Contains another ester group (R-C(=O)-O-R').

4. **Determining the Correct Answer**:
- From the analysis:
- **Option 1** (ketone) will react with 2,4-DNP to form an orange precipitate.
- **Options 2, 3, and 4** (esters and carboxylic acids) will not react to form an orange precipitate.
- Therefore, the compound that will give an orange precipitate when treated with 2,4-DNP is **Option 1**.

### Final Answer:
**Option 1** is the correct answer as it contains a ketone group that will react with 2,4-DNP to produce an orange precipitate.