(2025/2026) CHEM 219 MODULE 7
NEWEST EXAM QUESTIONS AND
CORRECT ANSWERS
What is the definition of a fused ring? Correct Answer In a
fused ring system, two (or more) rings are fused together
to form a larger molecule. To be fused means that each
ring shares two (or more) common atoms as a part of the
structure of each ring.
The molecule Indole has what ring fused to the C2-C3
bond of a pyrrole ring? Correct Answer Benzene
Adenine and guanine, two of the nitrogenous bases
present in DNA and RNA , contain what fused ring
heterocycle? Correct Answer Purine
Heterocycles Correct Answer Cyclic organic molecules in
which one or more carbon atoms are replaced by
heteroatoms - elements other than C or H. Largest class
of organic compounds known.
Most common heteroatoms... Correct Answer O, N, S
Two subgroups of heterocyclic compounds Correct
Answer Aromatic and Alliphatic (Non-Aromatic)
Examples of Non-Aromatic (Aliphatic) Heterocycles
Correct Answer Epoxides, Glucose
, Pyridine Correct Answer Six membered heterocyclic
analog of benzene.
One of the CH units of the (benzene) ring is replaced by a
N atom.
Aromatic
Tends to undergo substitution reactions rather than
addition (which would destroy aromaticity).
The substitution of the N atom in the ring changes many
properties of the molecule.
Pyridine Properties Correct Answer Miscible in most
organic solvents, and completely miscible with water.
Boiling point is 35 degrees above that of Benzene due to
dipole-dipole attractive forces.
Weak base and will react with strong acids to form
pyridinium salts.
The ability if pyridine to act as a base makes it suited to
act as a proton scavenger in acid producing reactions, like
the conversion of alcohols to alkyl chlorides using thionyl
chloride.
Electrophilic Aromatic Substitution (EAS) Correct Answer
An H is replaced by an electrophile.
Requires very harsh conditions and occurs very slowly.
Can be nitrated or brominated at very high temperatures
and with ver strong acid catalysis.
Electron withdrawal by the N makes the ring partially
positive and this not as receptive to attack by electrophiles
like NO2 or Br.
NEWEST EXAM QUESTIONS AND
CORRECT ANSWERS
What is the definition of a fused ring? Correct Answer In a
fused ring system, two (or more) rings are fused together
to form a larger molecule. To be fused means that each
ring shares two (or more) common atoms as a part of the
structure of each ring.
The molecule Indole has what ring fused to the C2-C3
bond of a pyrrole ring? Correct Answer Benzene
Adenine and guanine, two of the nitrogenous bases
present in DNA and RNA , contain what fused ring
heterocycle? Correct Answer Purine
Heterocycles Correct Answer Cyclic organic molecules in
which one or more carbon atoms are replaced by
heteroatoms - elements other than C or H. Largest class
of organic compounds known.
Most common heteroatoms... Correct Answer O, N, S
Two subgroups of heterocyclic compounds Correct
Answer Aromatic and Alliphatic (Non-Aromatic)
Examples of Non-Aromatic (Aliphatic) Heterocycles
Correct Answer Epoxides, Glucose
, Pyridine Correct Answer Six membered heterocyclic
analog of benzene.
One of the CH units of the (benzene) ring is replaced by a
N atom.
Aromatic
Tends to undergo substitution reactions rather than
addition (which would destroy aromaticity).
The substitution of the N atom in the ring changes many
properties of the molecule.
Pyridine Properties Correct Answer Miscible in most
organic solvents, and completely miscible with water.
Boiling point is 35 degrees above that of Benzene due to
dipole-dipole attractive forces.
Weak base and will react with strong acids to form
pyridinium salts.
The ability if pyridine to act as a base makes it suited to
act as a proton scavenger in acid producing reactions, like
the conversion of alcohols to alkyl chlorides using thionyl
chloride.
Electrophilic Aromatic Substitution (EAS) Correct Answer
An H is replaced by an electrophile.
Requires very harsh conditions and occurs very slowly.
Can be nitrated or brominated at very high temperatures
and with ver strong acid catalysis.
Electron withdrawal by the N makes the ring partially
positive and this not as receptive to attack by electrophiles
like NO2 or Br.
