Cellulose is a linear polymer of $$\beta $$ $$ - D - $$ glucose in which $${C_1}$$ of one glucose unit is connected to $${C_4}$$ of the other through $$\beta - D$$ glucosidic linkage. It does not undergo hydrolysis easily. However on heating with dilute $${H_2}S{O_4}$$ under pressure. It does undergo hydrolysis to give only $$D-$$ glucose.

$$$\left( {{C_6}{H_{10}}{O_5}} \right)n + n{H_2}O\buildrel {\,H + } \over \longrightarrow \mathop {n{C_6}{H_{12}}{O_6}}\limits_{D - Glu\cos e} $$$