Question

CH_3OCH_3 and CH_3OH can form a hydrogen bond with one another. Select True or False. True False

Answer 1

Answer: True

The requirement for hydrogen bonding between two molecules is that, atleast one molecule should contain a hydrogen attached to a highly electronegative atom (like F, O, N) and the other molecule should contain a highly electronegative atom.

CH₃OH contains a hydrogen atom attached to a highly electronegative atom, namely, oxygen. There is partial positive charge on hydrogen of -OH group and partial negative charge on oxygen.

There are two lone pairs of electrons on oxygen atom in dimethyl ether (CH₃OCH₃) as well as on oxygen atom in methanol (CH₃OH). High electronegativity of oxygen and presence of lone pairs of electrons facilitates hydrogen bonding between oxygen of dimethyl ether (CH₃OCH₃) and hydrogen of -OH group in methanol (CH₃OH).

(Hydrogen bonding between two methanol molecules will be prevalent; there will be hydrogen bond between oxygen of one methanol molecule with hydrogen in -OH group of another methanol molecule.)

Representing CH₃OCH₃ as (CH₃)₂O , hydrogen bonding between the two molecules is illustrated below,

(CH₃)₂O^.......H-O-CH₃