NEET 2026
- Exam
- NEET
- Year
- 2026
- Subject
- Chemistry
- Chapter
- Chapter
NEET 2026 · Chemistry · Chapter
An organic compound 'Y' has the structure shown in the figure....
An organic compound 'Y' has the structure shown in the figure.
Compound 'Y' is treated with an alkaline solution of ammoniacal silver nitrate and heated. Which of the following represents the correct IUPAC name of the major organic species present in the resulting reaction mixture?
Options
- A4,4-dimethyl-5-oxohexanoic acid
- B4,4-dimethyl-5-oxohexanoate ion
- C4,4-dimethylhexanedioate ion
- D5-hydroxy-4,4-dimethylhexanoate ion
Correct answer
B. 4,4-dimethyl-5-oxohexanoate ion
Step-by-step solution
Based on the given structure, compound 'Y' contains two functional groups: an aldehyde group () at one end and a ketone group () in the chain. Its IUPAC name is 4,4-dimethyl-5-oxohexanal.
The reagent given is an alkaline solution of ammoniacal silver nitrate, which is Tollens' reagent (). Tollens' reagent is a mild oxidizing agent that selectively oxidizes aldehydes to their corresponding carboxylate salts in an alkaline medium. It does not oxidize ketones under normal conditions.
Therefore, the aldehyde group in compound 'Y' will be oxidized to a carboxylate ion (), while the ketone group will remain unaffected. Since the reaction mixture is alkaline, the product will exist as a carboxylate ion rather than a free carboxylic acid.
Let's determine the IUPAC name of the resulting product:
1. The principal functional group is the carboxylate ion, so numbering starts from the carboxylate carbon (C-1).
2. The carbon chain has 6 carbon atoms, making the parent name 'hexanoate ion'.
3. At C-4, there are two methyl groups, giving the prefix '4,4-dimethyl'.
4. At C-5, there is a ketone group, giving the prefix '5-oxo'.
Combining these parts in alphabetical order, the IUPAC name of the major organic species in the alkaline reaction mixture is 4,4-dimethyl-5-oxohexanoate ion.
Answer: 4,4-dimethyl-5-oxohexanoate ion
The reagent given is an alkaline solution of ammoniacal silver nitrate, which is Tollens' reagent (). Tollens' reagent is a mild oxidizing agent that selectively oxidizes aldehydes to their corresponding carboxylate salts in an alkaline medium. It does not oxidize ketones under normal conditions.
Therefore, the aldehyde group in compound 'Y' will be oxidized to a carboxylate ion (), while the ketone group will remain unaffected. Since the reaction mixture is alkaline, the product will exist as a carboxylate ion rather than a free carboxylic acid.
Let's determine the IUPAC name of the resulting product:
1. The principal functional group is the carboxylate ion, so numbering starts from the carboxylate carbon (C-1).
2. The carbon chain has 6 carbon atoms, making the parent name 'hexanoate ion'.
3. At C-4, there are two methyl groups, giving the prefix '4,4-dimethyl'.
4. At C-5, there is a ketone group, giving the prefix '5-oxo'.
Combining these parts in alphabetical order, the IUPAC name of the major organic species in the alkaline reaction mixture is 4,4-dimethyl-5-oxohexanoate ion.
Answer: 4,4-dimethyl-5-oxohexanoate ion