Question

The aldehyde can be detected by which of the following?

• A. Tollens reagent
• B. Fehlings solution
• C. Schiffs reagent
• D. All of the above

Answer 1

Answer: (D)

The group to be detected by a reagent must give specific charge in colour or ppt. to show its presence.
Aldehyde + Tollens reagent $\to$ Silver mirror formed
Aldehyde + Fehlings solution $\to$ Red ppt. of $C{u}_{2}O$ is formed
Aldehyde + Schiffs reagent $\to$ Pink colouration
So, all the above reactions are used to detect presence of aldehyde group.