Answer to Question #113760 in Organic Chemistry for Jack

Question

Is galactose a D-sugar or L-sugar? How many lone pairs does galactose have? What are the functional groups on it?

Answer 1

Galactose is a D-sugar. There are 6 oxygen atoms in the molecule, each O atom has 2 lone pairs, so totally 12 lone pairs per molucule. It has 5 hydroxyl groups and 1 aldehyde group. The latter one is in the carbonyl CH=O conformation in the open-chain molecule or in the ether C(OH)-O-CH2 conformation in the circular molecule.