How many of the following pairs can form same osazone?
a) D-glucose and D-galactose, b) D-glucose and D-mannose, c) D-Ribose and D-Arabinore,
d) D-xylose and D-erythrose, e) D-glyceraldehyde and L-glyceraldehyde, f) D-allose and D-altrose

Osazones are a class of carbohydrate derivatives found in organic chemistry formed when sugars are reacted with phenylhydrazine.

Glucose, Fructose and Mannose forms same osazone. Ribose and Arabinose forms same osazone.

D-glucose, D-fructose, and D-mannose form the same osazone treated with excess phenyl hydrazine because they differ only 1st and 2nd carbon atoms which are transformed to the same form.

a) D-glucose and D-galactose, b) D-glucose and D-mannose, c) D-Ribose and D-Arabinore,
d) D-xylose and D-erythrose, e) D-glyceraldehyde and L-glyceraldehyde, f) D-allose and D-altrose