Question

The letter ‘D’ in carbohydrates signifies :

• A. dextrorotatory
• B. mode of synthesis
• C. its configuration
• D. its diamagnetic nature
  

Answer 1

Answer: (C)

its configuration

D and L just tells us the configuration of carbohydrate relative to (+)glyceraldehyde.

D means the OH group on the second last carbon (chiral) is to the right side (when the chain is properly oriented) and L means that the OH group is on the left side.

Note that proper orientation means that the chain is vertical and the principal functional group is at the top.

Also note that D and L have no relation with dextrorotatory and laevorotatory nature.

Option C is correct.