To identify the organic compound ‘A’ with the molecular formula C5H8O2, we need to analyze the information provided step by step. The reduction of ‘A’ to n-pentane indicates that ‘A’ is likely a ketone or an aldehyde, as these functional groups can be reduced to alkanes. The formation of a dioxime with hydroxylamine suggests the presence of a carbonyl group (C=O), which is characteristic of ketones and aldehydes. Additionally, the positive results for both the iodoform test and Tollen’s test provide further clues about the structure of ‘A’.
Analyzing the Functional Groups
Let’s break down the clues:
- Reduction to n-pentane: This suggests that ‘A’ is a carbonyl compound, likely a ketone or aldehyde, which can be fully reduced.
- Formation of dioxime: This indicates the presence of a carbonyl group, as dioximes are formed from ketones or aldehydes when reacted with hydroxylamine.
- Iodoform test: A positive iodoform test indicates that ‘A’ contains a methyl ketone (a ketone with a CH3 group adjacent to the carbonyl carbon) or an ethanol-derived structure.
- Tollen’s test: This test is positive for aldehydes and some ketones, particularly those that can be oxidized to form aldehydes.
Identifying the Compound
Given the molecular formula C5H8O2 and the tests mentioned, we can deduce that ‘A’ is likely 3-pentanone. Here’s why:
- 3-Pentanone has the structure CH3-CO-CH2-CH2-CH3, which fits the molecular formula C5H8O2.
- It contains a methyl group adjacent to the carbonyl, which allows it to give a positive iodoform test.
- When treated with hydroxylamine, it forms a dioxime, confirming the presence of the carbonyl group.
- 3-Pentanone can be oxidized to an aldehyde, which would give a positive Tollen’s test.
Structure of Compound A
The structure of 3-pentanone can be represented as follows:
CH3
|
CH3-CO-CH2-CH2-CH3
In this structure, the carbonyl group (C=O) is located at the second carbon, making it a ketone. The presence of the methyl group adjacent to the carbonyl confirms the iodoform test result.
Conclusion
In summary, the compound ‘A’ is 3-pentanone (C5H10O), which can be reduced to n-pentane, forms a dioxime with hydroxylamine, and gives positive results for both the iodoform and Tollen’s tests. This analysis illustrates how functional group tests can help deduce the structure of organic compounds effectively.
