Question

Which of the following alkenes are the most stables?
(A) $ (CH{}_3){}_2CH = CH{}_2 $
(B) $ CH{}_3CH = CHCH{}_3 $
(C) $ (CH{}_3){}_2C = C(CH{}_3){}_2 $
(D) $ CH{}_3CH = CH{}_2 $

Answer 1

Hint :Alkenes are hydrocarbons that have a carbon-carbon double bond. According to IUPAC an acyclic hydrocarbon with one double bond will be known as alkenes and for acyclic hydrocarbons with two or more than two double bonds will be called as cycloalkene.

Complete Step By Step Answer:
When we take a look at option C, $ 2,3 $ - dimethylbut- $ 2 $ -ene, is a tetra substituted alkene is known to be the most stable because, according to the saytzeff's rule, if a compound is more substituted the alkene, the more stable it is.

Additional Information:
Saytyzeffs rule also known as zaitsev's rule, states that a stable alkene is formed when there is a removal of hydrogen from the $ \beta $ (beta) carbon has a low number of hydrogen substituents . When elimination reaction takes place, this rule comes into picture. The compound which is the most substituted product would be the most stable and the most preferred. There is no generalization about the product stereochemistry, but only the regiochemistry of the elimination reaction. Elimination reaction of alkyl halides and alcohol results in different types of alkenes and this rule is used to predict the major product and minor product is predicted which is based on the number of alkyl groups attached to the alkene.

Note :
Alkenes are generally known to us colourless apolar compounds, which is kind of similar to alkanes but are more reactive. The simplest alkene is ethylene which is produced on a large scale.