`CH_(3)CH=CHCHO` is oxidised to `CH_(3)-CH=CHCOOH,` using oxidising agent as :

Options

A. Alkaline `KMnO_(4)`
B. Selenium dioxide
C. Osmium tetraoxide
D. Ammonical `AgNO_(3)`

Answer

To solve the problem of oxidizing the compound \( CH_3CH=CHCHO \) to \( CH_3CH=CHCOOH \) using an appropriate oxidizing agent, we need to analyze the structure and the functional groups involved.

### Step-by-Step Solution:

1. **Identify the Functional Groups**:
- The starting compound \( CH_3CH=CHCHO \) contains an aldehyde group (-CHO) and an alkene group (C=C).
- The target compound \( CH_3CH=CHCOOH \) contains a carboxylic acid group (-COOH) and retains the alkene group.

2. **Determine the Reaction Requirement**:
- We need to oxidize the aldehyde group to a carboxylic acid without affecting the alkene group. This requires a selective oxidizing agent.

3. **Evaluate the Oxidizing Agents**:
- **Alkaline KMnO4**: This is a strong oxidizing agent that can oxidize both the aldehyde and the alkene. Therefore, it is not suitable for this reaction.
- **Selenium Dioxide (SeO2)**: This oxidizing agent can also oxidize alkenes, converting them to allylic alcohols or further oxidizing them. Hence, it is not suitable for our needs.
- **Osmium Tetraoxide (OsO4)**: This reagent is primarily used for converting alkenes to cis-1,2-diols. Thus, it will also affect the alkene, making it unsuitable.
- **Ammonical Silver Nitrate (Tollens' Reagent)**: This is a mild oxidizing agent that selectively oxidizes aldehydes to carboxylic acids without affecting alkenes. This makes it the ideal choice for our reaction.

4. **Conclusion**:
- The appropriate oxidizing agent to convert \( CH_3CH=CHCHO \) to \( CH_3CH=CHCOOH \) is **Ammonical Silver Nitrate**.

### Final Answer:
The oxidizing agent used is **Ammonical AgNO3**.

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