All Organic Chemistry Resources
Example Questions
Example Question #11 : Identifying Aromatic Compounds
Assuming that this molecule is planar, determine whether this molecule is aromatic, and name the number of  electrons (
 molecular orbitals).
Aromatic, 6Â Â electrons
Non aromatic, 6Â Â electrons
Not aromatic, 8Â Â electrons
Aromatic, 8Â Â electrons
Not aromatic, 8Â Â electrons
There is no p orbital surrounding the Boron atom, so the ring does not have a fully conjugated pi system. In addition, there are 8Â Â electrons, which does not follow Huckel's rule (an aromatic system contains 4n+2 electrons). The pi electrons include the lone pair (not shown, but implicit) on the nitrogen atom, which is why the answers with "6 electrons" are not correct.
Example Question #12 : Identifying Aromatic Compounds
Assuming that this molecule is planar, determine whether this molecule is aromatic, and name the number of  electrons (notÂ
 molecular orbitals).Â
Not aromatic, 6Â Â electrons.Â
Not aromatic, 8Â Â electrons.
Aromatic, 6Â Â electrons.Â
Aromatic, 8Â Â electrons.
Aromatic, 6Â Â electrons.Â
The lone pairs on the two nitrogen atoms reside in sp2 orbitals, meaning they do not participate in resonance. Within the ring, there are three  bonds, meaning there are sixÂ
 electrons. Thus, the molecule is aromatic because it is planar and follows Huckel's rule.Â
Example Question #1 : Identifying Carbonyl Compounds
Identify the given organic functional group.
Aldehyde
Ester
Acid anhydride
Ketone
Carboxylic acid
Aldehyde
Aldehydes are carbonyls with one R-group and one hydrogen attached to the carbonyl carbon.
Example Question #1 : Identifying Carbonyl Compounds
Identify the given organic functional group.
Carboxylic acid
Ketone
Acetal
Aldehyde
Ester
Ketone
Ketones are carbonyls with two R-groups attached the the carbonyl carbon.
Example Question #2 : Identifying Carbonyl Compounds
Identify the given organic functional group.
Ester
Carboxylic acid
Acid anhydride
Acid halide
Amide
Acid halide
This is an acid halide, were X is any halogen (group VII). They are the most reactive of all the carboxylic acid derivatives.
Example Question #3 : Identifying Carbonyl Compounds
Identify the given organic functional group.
Ester
Carboxylic acid
Acid anhydride
Ketone
Aldehyde
Carboxylic acid
Carboxylic acids are composed of one R goup and a hydroxy group bound to the carbonyl carbon. The hydroxyl group gives the molecule acidic properties.
Example Question #1 : Identifying Carbonyl Compounds
Identify the given organic functional group.
Acetal
Ester
Acid anhydride
Hemiketal
Aldehyde
Hemiketal
This is a hemiketal. Hemiketals are formed from the reaction of a ketone with an alcohol. The alcohol attacks the carbonyl carbon, reducing the double bond and adding a hydroxyl group.
Example Question #4 : Identifying Carbonyl Compounds
Identify the given organic functional group.
Ketal
Hemiacetal
Acetal
Acid anhydride
Hemiketal
Ketal
Ketals have two -OR groups bound to a central carbon. The R groups attached to the oxygens are not necessarily the same. Ketals result from the reaction of a ketone with two equivalents of alcohol.
Example Question #5 : Identifying Carbonyl Compounds
Identify the given organic functional group.
Hemiacetal
Ester
Acid anhydride
Acetal
Carboxylic acid
Acid anhydride
Acid anhydrides are relatively reactive, since they have a fairly good leaving group (the conjugate base of a carboxylic acid) [COO-]. They are formed by reacting two carboxylic acids via dehydration synthesis.
Example Question #6 : Identifying Carbonyl Compounds
Identify the given organic functional group.
Imine
Amine
Ester
Amide
Ether
Amide
This is an amide. It is very unreactive since its leaving group is the conjugate base of an amine [HNR-].Â
All Organic Chemistry Resources
