Textbook Question
What is the major product of the reaction of 2-methyl-2-butene with each of the following reagents?
a. HBr
10. Addition Reactions
Hydrohalogenation
2:28 minutesProblem 12a(1)
Textbook Question
What is the major product of each of the following reactions?
1. 
Verified step by step guidance1
Step 1: Identify the type of reaction. The reaction involves an alkene reacting with HBr, which is an electrophilic addition reaction.
Step 2: Determine the regioselectivity of the reaction. According to Markovnikov's rule, the hydrogen atom from HBr will add to the carbon of the double bond that has more hydrogen atoms, while the bromine atom will add to the carbon with fewer hydrogen atoms.
Step 3: Analyze the structure of the alkene. The double bond is between a secondary carbon and a primary carbon. The secondary carbon has fewer hydrogens, so bromine will add to this carbon.
Step 4: Consider the formation of the carbocation intermediate. The addition of H+ to the primary carbon will result in the formation of a more stable secondary carbocation.
Step 5: Complete the reaction by adding Br- to the carbocation. The bromine ion will attack the positively charged secondary carbon, forming the major product.
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2mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Hydrohalogenation
Hydrohalogenation is an electrophilic addition reaction where a hydrogen halide (like HBr) adds across a double bond of an alkene. The reaction typically follows Markovnikov's rule, which states that the hydrogen atom from the hydrogen halide will attach to the carbon with the greater number of hydrogen atoms, leading to the formation of a more stable carbocation intermediate.
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General properties of hydrohalogenation.
Markovnikov's Rule
Markovnikov's rule is a principle used to predict the outcome of electrophilic addition reactions involving alkenes. It states that when HX (where X is a halogen) adds to an asymmetric alkene, the hydrogen atom will bond to the carbon atom with the most hydrogen substituents, while the halogen will bond to the carbon with fewer hydrogen substituents, resulting in the more stable product.
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Carbocation Stability
Carbocation stability is a key concept in organic chemistry that refers to the relative stability of positively charged carbon species (carbocations). Carbocations are stabilized by electron-donating groups and are more stable when they are tertiary (attached to three other carbons) compared to secondary or primary carbocations. This stability influences the pathway and product of reactions involving alkenes.
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