Question Video: Identifying the Major Product of the Reaction of Propene and Hydrogen Bromide | Nagwa Question Video: Identifying the Major Product of the Reaction of Propene and Hydrogen Bromide | Nagwa

Question Video: Identifying the Major Product of the Reaction of Propene and Hydrogen Bromide Chemistry • Third Year of Secondary School

Join Nagwa Classes

Attend live Chemistry sessions on Nagwa Classes to learn more about this topic from an expert teacher!

What is the major product produced in the addition reaction of hydrogen bromide and propene?

02:48

Video Transcript

What is the major product produced in the addition reaction of hydrogen bromide and propene? (A) Compound one, (B) compound two.

An addition reaction is a type of chemical reaction where two or more molecules combine to form a single type of molecular product. We are shown that the addition reaction of hydrogen bromide and propene could produce two different products. We need to determine which of the compounds is the major product of this reaction, or in other words which of the compounds is most likely to be produced.

Propene is an alkene, a compound which contains an electron-rich carbon-carbon double bond. Alkenes react with hydrogen halides, like hydrogen bromide, in a hydrohalogenation reaction, a type of addition reaction. Over the course of this reaction, the 𝜋 bond between the two carbon atoms will break as will the bond between the hydrogen and halogen atoms. This loss of bonds will allow for the formation of a new carbon-hydrogen bond and a new carbon-halogen bond. The product of this reaction is a haloalkane.

In this example, we chose to add the hydrogen atom to the carbon on the left and the halogen atom to the carbon on the right. But if this were reversed, the product would still be the same. This is because the starting alkene is symmetrical. Propene is an unsymmetrical alkene. This affects how the hydrogen and halogen atoms will add to the molecule.

In general, we can predict the major product of the hydrohalogenation of an unsymmetrical alkene using Markovnikov’s rule. Markovnikov’s rule states that the acidic hydrogen atom will add to the carbon of the double bond that has the greatest number of hydrogen substituents. Looking at propene, the carbon of the double bond that has the greatest number of hydrogen substituents is the carbon atom on the right. So during the reaction, the hydrogen of hydrogen bromide should form a bond with this carbon atom. This means that bromine must form a bond with the other carbon atom of the double bond, the carbon atom in the center of the structure.

Looking at the compounds, we can see that the compound which shows a new hydrogen atom bonded to the carbon on the right and a bromine atom bonded to the carbon in the middle of the structure is compound one. Therefore, the major product produced in the addition reaction of hydrogen bromide and propene is compound one, answer choice (A).

Join Nagwa Classes

Attend live sessions on Nagwa Classes to boost your learning with guidance and advice from an expert teacher!

  • Interactive Sessions
  • Chat & Messaging
  • Realistic Exam Questions

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy