1. Q3 (a)
Constitutional isomerism
Two or more molecules with the same molecular formula but different structural formula. In
other words, two or more molecules with same formula but different connectivity.
n-Butane and isobutane are examples of constitutional isomers, as are ethanol and
dimethyl ether. Constitutional isomers can also have different functional groups. For
example, both ethyl alcohol and dimethyl ether have the same molecular formula: C2H6O.
Stereoisomerism
Two molecules with the same constitution but different stereochemistry. As an example,
D-glucose is an aldohexose and has the formula C6H12O6. Four of its six carbon atoms are
stereogenic, which means D-glucose is one of 24=16 possible stereoisomers.