Describe the use of tollen's reagent to detect the presence of an aldehyde group.

Describe the use of tollen's reagent to detect the presence of an aldehyde group.

Tollen's reagent is a compound that will oxidise an aldehyde to form a silver precipitate (silver mirror), but will not oxidise ketones (since they can not be oxidised any further), hence can be used to distinguish between the two.

Identification Of Aldehyde & Ketone Group

At First We have to Identify Aryl Group : 

 We will use Brayde's Reagent to identify the Aryl Group.

Brayde's Reagent is 2,4-Dinitriphinyle Hydrazin. 

So it is also called 2,4-Dinitriphinyle Hydrazin Test.2,4-Dinitriphinyle Hydrazin itself is a yellow solution.

It will react with aryl group ( both Aldehyde & Ketone ) and will 

give 2,4-Dinitriphinyle Hydrazone precipitate.

2,4 Dinitrophenylhydrazine Test