Chapter 5, Problem 5.1P

Interpretation Introduction

Interpretation: An explanation corresponding to the fact that cellulose is water insoluble by considering its three-dimensional structure is to be stated.

Concept introduction: Carbohydrates are polyhydroxy aldehyde and ketones, with an empirical formula ${\text{C}}_{\text{m}}{\left({\text{H}}_{\text{2}}\text{O}\right)}_{\text{n}}$. Glucose is a monosaccharide (or simple sugar) having a molecular formula of ${\text{C}}_{\text{6}}{\text{H}}_{\text{12}}{\text{O}}_{\text{6}}$.

Cellulose is an insoluble complex carbohydrate i.e. polysaccharide consisting of a large number of glucose units. It is a linear polymer of $\text{β-D-glucose}$ and the basic structural component of plant cell walls. It is also an excellent fiber.

Answer to Problem 5.1P

An explanation corresponding to the fact that cellulose is water insoluble by considering its three-dimensional structure is rightfully stated.

Explanation of Solution

Cellulose is a polysaccharide with a molecular formula ${\left({\text{C}}_{\text{6}}{\text{H}}_{\text{10}}{\text{O}}_{\text{5}}\right)}_{\text{n}}$. It is formed by the monomers of glucose unit. By considering its three-dimensional structure, it is water insoluble because of its high molecular weight.

In cellulose, the hydroxyl $\left(\text{OH}\right)$ groups are attached to each other by intermolecular hydrogen bonding. Due to which the formation of sheets in three dimensional structure of cellulose occurs. Therefore, the structure of cellulose becomes inflexible. Hence, in spite of having many hydroxyl groups, cellulose is water insoluble.

Conclusion

Cellulose is water insoluble due to its high molecular weight and inflexible structure.