Question

The disaccharide sucrose gives negative touens test while the disaccharide maltesa gives positive touens test

Answer 1

Answer:

Sucrose will form an open chain structure. The carbon that can change from a hemi-ketal or hemi-acetal to a ketone or aldehyde is called the "anomeric" position. If the anomeric carbon is blocked (i.e., instead of -OH it is -OCH3 or -O-sugar or -O-almost-anything) the sugar cannot open up and the sugar is non-reducing.