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Addition of HX across a double bond

Addition of HX across a double bond. And Carbocation rearrangement. Addition of HX across a double bond. An acid, HX, such as HCl, HBr and HI add across a double in this fashion. This is called Markovnikov addition of HX across a double bond. Markovnikov Addition.

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Addition of HX across a double bond

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  1. Addition of HX across a double bond And Carbocation rearrangement

  2. Addition of HX across a double bond An acid, HX, such as HCl, HBr and HI add across a double in this fashion. This is called Markovnikov addition of HX across a double bond.

  3. Markovnikov Addition Markovnikov’s rule states that when adding something across a double bond, the anion (negative ion) will bond with the more substituted carbon. Example: Notice how there is no distinct stereochemistry. This is because the ion can attack either side of the carbon.

  4. Quick Review: Draw the products of the following two reactions:

  5. Rearrangement The anion, in normal circumstances, will always attack the most substituted carbon in the molecule, not just the most substituted carbon in the double bond. Example:

  6. Why does rearrangement occur: An intermediate is formed in the reaction between HCl and an Alkene. It follows by this mechanism: In this intermediate, a carbocation is formed. Carbocations can easily rearrange to a more stable carbon.

  7. Carbocation stability A primary carbocation is a carbocation bonded to one other carbon. A secondary carbocation is a carbocation bonded to two other carbons. It is more stable than a primary carbocation. A tertiary carbocation is a carbocation bonded to three other carbons and is more stable than a secondary carbocation. The general order is 1º< 2º< 3º

  8. What type of carbocations are these? Which are the most stable?   

  9. INCORRECT

  10. CORRECT

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