Question

which of the following lewis diagrams represents the substance that would exhibit the most significant hydrogen bonding in a pure liquid sample?
a
h h h h
h - c - c - o - c - c - h
h h h h
b
h h h h h
h - c - c - c - c - c - h
h h h h h
c
h h h
h - c - c - c - n - h
h h h h
d
h :o: h
h - c - c - c - h
h h h

Explanation:

Hydrogen bonding occurs when hydrogen is bonded to a highly electronegative atom (N, O, F). In option A, there is an oxygen - containing functional group (ether), but no O - H bond. Option B has only C - H bonds and no electronegative atoms for hydrogen bonding. Option C has an N - H bond, which can participate in hydrogen bonding. Option D has a carbon - oxygen double bond but no O - H or N - H bonds for significant hydrogen bonding. Among these, the N - H bond in option C can form hydrogen bonds, and since hydrogen bonding is stronger when the electronegative atom is more electronegative and the bond is more polar, and N - H can form hydrogen bonds, it is likely to exhibit significant hydrogen bonding compared to the others.

Answer:

C. H - C - C - C - N - H (with hydrogens attached to carbons and lone - pairs on nitrogen)