Question

What is the main product of the reaction between \[2 - \]methyl propene with \[HBr\]?
A. \[1 - \]bromo butane
B. \[1 - \]bromo\[ - 2 - \]methyl propane
C. \[2 - \] bromo butane
D. \[2 - \] bromo\[ - 2 - \]methyl propane

Answer 1

Hint: According to Markovnikov's rule, when an acid hydrogen is introduced to an unsymmetrical alkene, it attaches to the carbon with fewer alkyl substituents than a halide group, which attaches to the carbon with more alkyl substituents.



Formula Used:

Complete step-by-step answer:In order to know that the hydrocarbon \[2 - \]methylpropene has the formula \[{(C{H_3})_2}C = C{H_2}\]. It is one of the four isomers of butylene, an alkene with four carbon branching molecules. It is a gas that burns without colour and has significant industrial value. While an inorganic substance with a formula \[HBr\] which is hydrogen bromide. A constant-boiling azeotrope mixture made up of aqueous solutions containing\[47.6\% \,HBr\] by mass boils at\[124.3{\text{ }}^\circ C\]. Less concentrated solutions are boiled in order to liberate energy until the composition of the constant-boiling combination is attained.

Under Markovnikov's Rule, the hydrogen halide attaches to the carbon with the more hydrogen substituents when it is added to an asymmetric alkene and the halide group which are attaches with more alkyl substituents. And the rule can also be expressed in the alternative way that the \[(X)\] component is added to the carbon while the hydrogen atom is added to the carbon with the bigger amount of hydrogen atoms.
The creation of the most stable carbocation during the addition process serves as the chemical foundation for Markovnikov's Rule. When \[HBr\] is added to \[2 - \]methyl propene then it forms the most stable carbocation which is according to the Markovnikov rule. Next, \[Br\] is added to the carbocation to create \[2 - \]bromo\[ - 2 - \]methyl propane.
Therefore, the correct option is: (D) \[2 - \] bromo\[ - 2 - \]methyl propane.



Option ‘ ’ is correct

Additional Information:

Note: It should be noted that a carbocation is created by the electrophilic addition of an acidic hydrogen ion or proton to an alkene. It has greater carbocation stability. The carbocation that has the most alkyl substituents on its carbon holds the positive charge, as is well known, making it the most stable carbocation. This is the cause of the majority of the product's addition of the halide to the carbon, which has more alkyl groups than usual.