Answer
C-2 epimers of monosaccharide form similar osazones and thus have the same melting point.
Glucose and mannose are C-2 epimers; galactose and talose are also C-2 epimers. So ozasones of glucose and mannose have the same melting point. Similarly, ozasones of galactose and talose have the same melting point.
Work Step by Step
C2 carbon of aldoses combines with phenyl hydrazine to form the osazone molecule. This process eliminates functional groups at C-2. So C-2 epimers, which differ only at C-2 carbon, will form similar ozasones.
