Q55 E. - Organic Chemistry (Mcmurry)

Question

On reaction with hydrogen gas by a platinum catalyst, ribose (Problem 5-54) is converted into ribitol. Is ribitol optically active or inactive? Explain.

Step-by-Step Solution

Answer

A ribitol is an optically inactive compound.

Optically active compounds

Optical active compounds are those which are capable of rotating plane-polarized light. Meso compounds are optically inactive compounds. For a compound to be optically active, it must have a chiral center.

Find out if ribitol is optically active or inactive

On catalytic hydrogenation (), ribose containing aldehyde converts into a hydroxyl group. When the plane of symmetry is drawn inside the molecule so that two halves of ribitol become mirror images of one another, this resulting compound is meso compound and, hence, optically inactive. 

                                            Conversion of Ribose to Ribitol