Answer:
Hexane: 2 signals
Isohexane: 3 signals
3-methylpentane: 3 signals
2,2-dimethylbutane: 2 signals
Diisopropyl: 3 signals
Explanation:
The number of signals in the ¹H NMR spectrum is equivalent to the number of different environments that the hydrogen atoms are in.
The hexane molecule, for example, has its hydrogen atoms in two different environments. The first one, -CH₃, where one carbon atom is bonded to 3 hydrogen atoms. And the second one, -CH₂, where the carbon atom is bonded with two hydrogen atoms. Therefore, there will be two signals in the ¹H NMR spectrum.
The same explanation is valid for the other molecules, which are represented in the picture attached. The different environment hydrogen atoms are represented by different colours.
