Assertion : Maltose is a reducing sugar which gives two moles of $\text{D}$ -glucose on hydrolysis.Reason : Maltose has a $1,4$ -$\beta$ -glycosidic linkage.

Maltose is indeed a reducing sugar that yields two moles of $\text{D}$ -glucose upon hydrolysis. However, the linkage in maltose is an $\alpha$ -glycosidic linkage ($\alpha$ -$1,4$), not a $\beta$ -linkage. The assertion is true, but the reason is false.