Question

Corn is a valuable source of industrial chemicals. For example, furfural is prepared from corncobs. It is an important solvent in synthetic rubber manufacturing, and it is reduced to furfuryl alcohol, which is used to make polymer resins. Furfural can also be oxidized to 2-furoic acid. furfuryl alcohol furfural 2-furoic acid.

a) Which of these compounds can form H bonds? Draw structures in each case.

b) The molecules of some substances can form an “internal” H bond, that is, an H bond within a molecule. This takes the form of a polygon with atoms as corners and bonds as sides and an H bond as one of the sides. Which of these molecules is (are) likely to form a stable internal H bond? Draw the structure.(Hint: Structures with 5 or 6 atoms as corners are most stable.)

Short answer

(a) The compounds which can form intermolecular H-bonds are furfuryl alcoholand 2-furoic acid.

(b) The2-furoic acidcompound can form an internal hydrogen bonding. It can form stable internal H-bonding as shown below.

Step-by-step solution

Step 1: Definition  

Hydrogen bonding is the bonding between the two different molecules that approach each other. Hydrogen bonding is the kind of weak intermolecular force ofattraction between the electronegative atom and electropositive atomwhich can be of the same molecule or a different molecule.

Intermolecular hydrogen bonding can form bonding between the electronegative atom and electropositive atom of different elements.

Intramolecular hydrogen bonding can form bonding between the electronegative atom and electropositive atom of the same atom.

Subpart (a)The compounds that can form H bonds. 

The compound furfuryl alcohol consists of the electronegative O-atom and Electropositive H-atom. There is a weak intramolecular force of attraction.

Compound2-furoic acidshows the carboxylic acid (COOH-atom) on both sides of the molecule,there is electronegative O-atom and electropositive H-atom.

Subpart (b) The molecule that is likely to form a stable internal H bond.

2-furoic acid can form the intramolecular hydrogen bonding between the electronegative O-atom and electropositive H-atom in the same molecule.