question_answer

Directions : In the following question more than one of the answers given may be correct. Select the correct answer and mark it according to the code:

Which of the following statements are true? (1) Maltose forms an osazone (2) Lactose undergoes mutarotation (3) Galactose is a\[{{C}_{4}}-\]epimer of glucose (4) In starch, the glucose units are linked by \[\beta -\]linkages

A)  1, 2 and 3 are correct

B)  1 and 2 are correct

C)   2 and 4 are correct

D)  1 and 3 are correct

Correct Answer: A

Solution :

                 Maltose,\[({{C}_{12}}{{H}_{22}}{{O}_{11}}),\]a disaccharide, reacts with phenyl hydrazine to give an osazone \[{{C}_{12}}{{H}_{20}}{{O}_{9}}{{(=N,NH{{C}_{6}}{{H}_{5}})}_{2}}.\]All monosaccharide and reducing disaccharide undergo mutarotation. The structure of glucose and galactose are as Thus, galactose is C-4 epimer of glucose. In starch, the glucose units are linked by\[\alpha -\]inkages.