NEET 2026
- Exam
- NEET
- Year
- 2026
- Subject
- Chemistry
- Chapter
- Chapter
NEET 2026 · Chemistry · Chapter
To prepare Fehling's reagent for the identification of aliphatic...
To prepare Fehling's reagent for the identification of aliphatic aldehydes, aqueous copper sulphate is mixed with an alkaline solution of a complexing agent. This agent prevents the precipitation of cupric hydroxide by forming a soluble complex. The complexing agent used is:
Options
- APotassium iodide
- BAmmonium hydroxide
- CSodium potassium tartrate
- DSodium citrate
Correct answer
C. Sodium potassium tartrate
Step-by-step solution
Fehling's reagent is prepared by mixing two solutions: Fehling's A and Fehling's B.
Fehling's A is an aqueous solution of copper sulphate ().
Fehling's B is an alkaline solution of sodium potassium tartrate, which is also known as Rochelle salt.
When these two solutions are mixed, the tartrate ions act as a chelating agent and form a soluble deep blue complex with the cupric ions (). This complexation prevents the precipitation of cupric hydroxide () in the strongly alkaline medium.
Therefore, the complexing agent used is sodium potassium tartrate.
Answer: Sodium potassium tartrate
Fehling's A is an aqueous solution of copper sulphate ().
Fehling's B is an alkaline solution of sodium potassium tartrate, which is also known as Rochelle salt.
When these two solutions are mixed, the tartrate ions act as a chelating agent and form a soluble deep blue complex with the cupric ions (). This complexation prevents the precipitation of cupric hydroxide () in the strongly alkaline medium.
Therefore, the complexing agent used is sodium potassium tartrate.
Answer: Sodium potassium tartrate