When 1 mol of maltose is subjected to acid-catalysed hydrolysis, it yields

Options

A. 2 mol of `beta - D - (+) -` glucose
B. 1 mol of `alpha - D - (+) -` glucose and 1 mol of `beta - D - (+) -` glucose
C. 2 mol of `alpha - d - (+) -` glucose
D. `½ mol` of `alpha - D-` glucose and `1½ mol` of `beta - D - (+) -` glucose

Answer

C

Explanation

When maltose is hydrolysed with dilute acids or by the enzyme maltase, it yeilds tow moles of `alpha-D-(+)-` glucose per mole.
Hydrolysis by acid to give a new reducing group (two reducing `D - (+) -` glucose molecules in place of one `(+) - ` maltose molecule ) is characterstic of glycosides, hydrolysis by the enzyzme maltase is characteristic of alpha glucosides.
A glycoside is an aceral formed by interaction of an alcohol with a carbonyl group of a carbohydrate, in this case the alcohol concerned can only be a second molecules of `D - (+) -` glucose, `(+)-` Maltose contains two `D - (+) -` glucose units, joined by an alpha - glucoside linkage between the carbonyl group of one `D - (+) -` glucose unit and an `-OH` group of the other.