Write structural formulas for all the constitutional isomers that have the given molecular...

Write structural formulas for all the constitutional isomers that have the given molecular formula.

(a) C₂H₇N

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(b) C₃H₇Cl

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(c) C₃H₈O

Sample Solution (a) The molecular formula C₂H₇N requires 20 valence electrons. Two carbons contribute a total of eight, nitrogen contributes five, and seven hydrogens contribute a total of seven. Nitrogen and two carbons can be connected in the order CCN or CNC. Assuming four bonds to each carbon and three to nitrogen, we write these connectivities as

Place a hydrogen on each of the seven available bonds of each framework.

The nine bonds in each structural formula account for 18 electrons. Add an unshared pair to each nitrogen to complete its octet and give a total of 20 valence electrons as required by the molecular formula.

These two are constitutional isomers.