Intro:
The aim of this practical was to work with several different sugars and a solution called Benedicts' reagent. We see how sugars react as reducing agents.
Test Tube Solution Colour
Result:
Aldaydes have a carboxyl group + function group + hydrogen.
Ketones have a carboxyl group + functional group.
Fructose and glucose are reduceing sugars, monosaccharides and therefore a reaction takes place the solution turns brick red after it has been heated.
Lactose and sucrose are disaccharides and therefore no reaction takes place so the solutions remain blue brown
Note: Aldehydes are CHO, ketones are C=O
ReplyDeleteWhy is fructose (a ketose) able to work as a reducing sugar? To be a reducing sugar, a sugar should ahve a free aldehyde group, i.e. be an aldose.
Again there is not so much by way of a discussion.
Steve