Question: 64. Fehling’s solution ‘A’ is
(1) aqueous copper sulphate
(2) alkaline copper sulphate
(3) alkaline solution of sodium potassium tartrate (Rochelle’s salt)
(4) aqueous sodium citrate
Answer: Option (1)
Explanation:
Fehling’s solution is used to test the presence of aldehydes and reducing sugars.
It consists of two separate solutions known as Fehling’s solution A and Fehling’s solution B.
Fehling’s solution A is an aqueous solution of copper sulphate containing
\mathrm{Cu^{2+}} ions.
Fehling’s solution B is an alkaline solution of sodium potassium tartrate, also known as Rochelle’s salt.
When both solutions are mixed in equal proportions, a deep blue coloured complex is formed,
which reacts with aldehydes or reducing sugars.
Therefore, Fehling’s solution A is aqueous copper sulphate
and the correct answer is Option (1).