The chemical reaction of 2 butene and HCl yields what product? ► View Available Hint(s)
Submit Part B
In an addition reaction of water (HOH) to an unsymmetrical alkene, the hydrogen adds to the carbon in the double bond:
- that has the smaller number of hydrogen atoms attached
- that has the greater number of hydrogen atoms attached
- that has the smaller number of carbon atoms attached
Submit Part C
The major product of the reaction of methyl-2-pentene with HCl is:
- 4-chloro-3-methylpentane
- 1-chloro-3-methylpentane
- 3-chloro-3-methylpentane
- 2-chloro-3-methylpentane
The correct answer and explanation is:
Answers:
Part A: The reaction of 2-butene with HCl yields 2-chlorobutane as the major product.
Part B: In the addition reaction of water (HOH) to an unsymmetrical alkene, the hydrogen adds to the carbon in the double bond that has the greater number of hydrogen atoms attached. (This follows Markovnikov’s rule.)
Part C: The major product of the reaction of methyl-2-pentene with HCl is 3-chloro-3-methylpentane.
Explanation (300 words):
The reaction of 2-butene with hydrogen chloride (HCl) follows an electrophilic addition mechanism. Since 2-butene is symmetrical (i.e., the double bond is between carbon-2 and carbon-3), HCl adds across the double bond according to Markovnikov’s rule. This rule states that the hydrogen atom (H⁺) adds to the carbon that already has more hydrogen atoms, while the chloride ion (Cl⁻) attaches to the more substituted carbon. As a result, 2-chlorobutane is the major product.
For the addition of water (HOH) to an unsymmetrical alkene, Markovnikov’s rule applies again. The hydrogen from the water molecule will add to the carbon with more hydrogens, while the hydroxyl group (–OH) will attach to the more substituted carbon. This stabilizes the carbocation intermediate, making the reaction more favorable.
In the reaction of methyl-2-pentene with HCl, we first identify the most stable carbocation intermediate. When H⁺ adds to the double bond, it creates a tertiary carbocation, which is the most stable. The chloride ion (Cl⁻) then attacks the carbocation, leading to the formation of 3-chloro-3-methylpentane, which is the major product.
Thus, these reactions follow predictable patterns based on carbocation stability and Markovnikov’s rule, ensuring the most stable product forms.
Now, let’s generate an image illustrating the reaction mechanisms for these transformations.
Here is an image illustrating the electrophilic addition reactions of 2-butene with HCl and methyl-2-pentene with HCl, showing the formation of 2-chlorobutane and 3-chloro-3-methylpentane, respectively. The diagram includes stepwise mechanisms with labeled molecular structures and electron movement arrows. Let me know if you need any modifications!
