Question

Indicate whether hydrogen bonding is present in the following compounds or mixtures. If hydrogen bonding is present, indicate how two molecules can hydrogen bond. For example, in a mixture of water and methanol the Hof the H₂O can hydrogen bond to the O in the CH₃OH. Also possible is that the OH of the CH₃OH can hydrogen bond to the O of the H₂O. (Of course, the H on one H₂O can hydrogen bond to the O on another H₂O, and the H in CH₃OH can hydrogen bond to the O in another CH₃OH.)

dimethyl ether

dimethyl ether and ethanol

acetone and water

Answer 1

Hydrogen bond: Hydrogen bond is the electrostatic interactions between the highly electronegative atoms like F/O/N and the H atom bonded to one of this electronegative atom in same or different molecules. Depending on this definition the possibility of presence or absence of H-Bonding is decided.

1. Dimethyl ether: In Dimethyl ether one of the most electronegative atoms i.e. O is present but no H is bonded to O or F/N present hence NO H-Bonding present in Dimethyl ether.
2. Dimethyl ether and Methanol: As we can see that Dimethyl ether has an electronegative atom O and the Methanol molecule having O as well as H bonded to O. Hence in Dimethyl ether and Methanol mixture 2 in two ways H bonding is present viz. i) Between ether O and alcohol’s H and ii) between O of one alcohol and H of anathor alcohol.
3. Acetone and water: 2 ways H-Bonding present as we can see in diagram.