Question
Chemistry Question on Chemical Reactions
An alkaline solution of...... and citrate ions is called:
A
silver nitrate, Fehlings solution
B
cupric sulphate, Schiffs reagent
C
silver chloride, Tollens reagent
D
cupric sulphate, Benedicts solution
Answer
cupric sulphate, Benedicts solution
Explanation
Solution
Benedicts solution: It is an alkaline solution of cupric ion complexed with citrate ions. When Benedict solution is used to oxidise an aldehyde, the complexed cupric ion (deep blue) is reduced to cuprous oxide (red). The presence of red precipitate of cuprous oxide serve as an indication of an aldehyde group in a molecule. R−CHO+2Cu(OH)2+NaOH R−COONa+(red)Cu2O+3H2O