The polarity of the carbonyl group is manifest in the physical properties of carbonyl compounds. Boiling points for the lower members of a series of aldehydes and ketones are \(50\)-\(80^\text{o}\) higher than for hydrocarbons of the same molecular weight; this may be seen by comparing the data of Table 16-2 (physical properties of aldehydes and ketones) with those in Table 4-1 (physical properties of alkanes). Table 16-2 : Physical Properties of Aldehydes and Ketones The water solubility of the lower-molecular-weight aldehydes and ketones is pronounced (see Table 16-2). This is to be expected for most carbonyl compounds of low molecular weight and is the consequence of hydrogen-bonding between the water and the electronegative oxygen of the carbonyl group: