Question

Out of the following compounds .
`I.` Pent `-1-`ene,
`II.` Pent `-2-`ene
`III.` `2-`Methyl but `-1-`ene
`IV.` `2-`Methyl bu`-2-`ene.
Which pair of the lowes and the highest heats of combustion, respectively ?
A. `(IV)` and `(I)`, respectively
B. `(I)` and `(IV)`, respectively
C. `(II)` and `(III)`, respectively
D. `(III) and `(II)`, respectively

Answer 1

Correct Answer - A
More`-` stable or more `-` substituted alkene has the lowest (more negative `(DeltaH_(C)^(@), DeltaH_("formation")`, and `DeltaH_(h)^(@))`
The order of stability of alkene `:IV gt III gt II gt I`.
So the lowest `Deltah_(C)^(@)` is to `(IV)` and the highest is of `(I)`.