Arrange the following isomeric alkenes in order of increasing stability and give your reasons: `(CH_(3))_(2)C=C(CH_(3))_(2)[I],CH_(2)=CHCH_(2)CH_(2)CH_(3)[II]`
`CH_(3)CH=CHCH(CH_(3))(2)[III],`
`CH_(3)CH=C(CH_(3))CH_(2)CH_(3)[IV]`

Explanation

The stability of an alkene is determined by the number of hyperconjugation structures, which in turn is dictated by the number of `alpha` - H - atoms (with respect to the olefinic carbons) present in the molecule. The greater the number of hyperconjugation structures, the higher is the stability of the alkene. Now the number of `alpha` - H - atoms in the alkene I,II,III and IV are 12, 2, 4 and 8 respectively. Thus stability of the alkanes follows the sequence : `IIltIIIltIVltI`.