Consider water and glycerol, $\mathrm{CH}_{2}(\mathrm{OH}) \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_{2} \mathrm{OH}$. (a) Would you expect them to be miscible in all proportions? (b) List the intermolecular attractions that occur between a water molecule and a glycerol molecule.

For water, the molecular formula is H₂O, which has two hydrogen atoms bonded to one oxygen atom with a bent molecular shape. It's a polar molecule with a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom. Glycerol has the molecular formula CH₂(OH)CH(OH)CH₂(OH). It contains three hydroxyl groups (OH) and has a linear molecular shape. The presence of hydroxyl groups makes glycerol a polar molecule as well.

Since both water and glycerol are polar molecules, they should be miscible according to the "like dissolves like" principle. Polar molecules generally dissolve in polar solvents, and water is considered a universal polar solvent. (a) So, we would expect water and glycerol to be miscible in all proportions.

(b) There are two main types of intermolecular attractions that can occur between water and glycerol molecules: 1. Hydrogen bonding: Due to the presence of polar O-H groups in both water and glycerol, they can form hydrogen bonds with each other. The oxygen atom in water can form a hydrogen bond with a hydrogen atom from the hydroxyl group in glycerol. Similarly, the oxygen atom in glycerol can form a hydrogen bond with a hydrogen atom of water. 2. Dipole-dipole interactions: Both water and glycerol are polar molecules, which means that they have a positive and a negative end (a dipole moment). The positive end of one molecule can attract the negative end of another, leading to dipole-dipole interactions between water and glycerol molecules.