Question 22.9: Consider the molecule C3H6Cl2, which is derived from propane...
Consider the molecule C_{3}H_{6}Cl_{2}, which is derived from propane, C_{3}H_{8}, by substituting two Cl atoms for H atoms. Draw the structural isomers of C_{3}H_{6}Cl_{2}.
1. All these compounds have three carbon atoms, hence the same skeleton.
C-C-C
Note that the terminal C atoms are equivalent. The middle C atom is not.
2. Bond 2 Cl atoms to the second C atom for the first isomer, and 2 Cl atoms to the terminal C atom for the second isomer.
C-\overset{\underset{|}{Cl} }{\underset{\overset{|}{Cl} }{C}}-C and C-C-\overset{\underset{|}{Cl} }{\underset{\overset{|}{Cl} }{C}}
3. Bond a Cl atom to each terminal C atom for the third isomer.
\overset{\underset{|}{Cl} }{C}-C- \overset{\underset{|}{Cl} }{C}4. Bond a Cl atom to a terminal C atom and the other Cl atom to the middle C atom for the fourth isomer.
\overset{\underset{|}{Cl} }{C}- \overset{\underset{|}{Cl} }{C}-C-5. Add the appropriate number of H atoms to the C atoms so that there are four bonds around each C atom.
CH_{3}-CH_{2}-\overset{\underset{|}{Cl} }{\underset{\overset{|}{Cl} }{C}} -H CH_{3}-\overset{\underset{|}{Cl} }{\underset{\overset{|}{Cl} }{C}}-CH_{3} H-\overset{\underset{|}{H} }{\underset{\overset{|}{Cl} }{C}}-CH_{2}-\overset{\underset{|}{H} }{\underset{\overset{|}{Cl} }{C}}-H CH_{3}-\overset{\underset{|}{H} }{\underset{\overset{|}{Cl} }{C}}-\overset{\underset{|}{H} }{\underset{\overset{|}{Cl} }{C}}-H