Chapter 12, Problem 7PEB

Glycerol is sometimes added to candy to keep it soft; it has a structural formula of

$\begin{array}{ccccc}& & \text{H}& & \\ & & \text{|}& & \\ \text{H}& {}^{\text{\_\_}}& \text{C}& {}^{\text{\_\_}}& \text{OH}\\ & & \text{|}& & \\ \text{H}& {}^{\text{\_\_}}& \text{C}& {}^{\text{\_\_}}& \text{OH}\\ & & \text{|}& & \\ \text{H}& {}^{\text{\_\_}}& \text{C}& {}^{\text{\_\_}}& \text{OH}\\ & & \text{|}& & \\ & & \text{H}& & \end{array}$

To what organic functional group does glycerol belong?