Solubility of glycerol (propan-1, 2, 3-triol), an odourless, colourless and viscous liquid. Molecules of glcerol are highly polar due to the presence of three polar hydroxyl (-OH) groups. These hydroxyl groups readily form hydrogen bonds with polar water molecules when mixed. Glycerol dissolves slowly as it takes time for the water molecules to disrupt the extensive hydrogen bonding between the glycerol molecules themselves. As such, initially it forms a dense layer below the layer of water. However when stirred it is seen to dissolve completely.