Electrophilic addition

    Cards (65)

    • What are electrophiles?
      Electron pair acceptors attracted to electron density
    • Why are alkenes susceptible to electrophilic attack?
      High electron density in carbon-carbon double bond
    • What do curly arrows represent in reaction mechanisms?
      Movement of electron pairs to break/form bonds
    • What happens to the bromine molecule as it approaches the alkene?
      Electrons are repelled, creating partial charges
    • What does the negatively charged bromide ion do after formation?
      It forms a new bond with the carbocation
    • Why does bromine water turn colorless during the reaction?
      Bromine atoms bond to carbon, losing color
    • What are the characteristics of electrophiles and nucleophiles in the context of alkenes?
      • Electrophiles:
      • Electron pair acceptors
      • Attracted to high electron density
      • Often have a positive charge

      • Nucleophiles:
      • Electron pair donors
      • Repelled by high electron density
    • What is the significance of the bromine water test in organic chemistry?
      • Confirms presence of carbon-carbon double bonds
      • Color change from orange to colorless indicates reaction
      • Useful for identifying unsaturated hydrocarbons
    • What is the term for the breaking of a covalent bond where both electrons go to one atom?
      Heterolytic fission
    • How do halogen molecules differ from hydrogen halides in terms of dipoles?
      Halogen molecules have an induced dipole
    • What are the key stages in the electrophilic addition of a halogen molecule to an alkene?
      1. Bromine approaches alkene, inducing a dipole.
      2. Alkene's pi bond attracts positive bromine, forming a bond.
      3. Bromine bond breaks (heterolytic fission), creating a carbocation and bromide ion.
      4. Bromide ion bonds with carbocation, forming the product.
    • What are the differences between adding a halogen and a hydrogen halide to an alkene?
      • Halogen molecules have an induced dipole; hydrogen halides have a permanent dipole.
      • Adding hydrogen halides to asymmetric alkenes produces major and minor products; halogens produce one product.
    • What is an alkene?
      Unsaturated hydrocarbons with a double bond
    • What is a polar bond or molecule?
      Electrons are unevenly distributed between atoms
    • What are electrophiles?
      Electron pair acceptors attracted to electron density
    • Why are alkenes susceptible to electrophilic attack?
      They have a region of high electron density
    • What do curly arrows represent in reaction mechanisms?
      Movement of electron pairs in bond formation
    • Why can bromine react with an alkene despite being non-polar?
      It gets polarized by the alkene's double bond
    • What happens to the bromine molecule as it approaches the double bond?
      Electrons are repelled, creating partial charges
    • What does the partial positive charge on bromine indicate?
      It is electron deficient and can accept electrons
    • What is formed when the double bond breaks during the reaction?
      A carbocation intermediate is formed
    • What is a carbocation?
      An ion with a carbon atom and positive charge
    • What happens to the bromide ion during the reaction?
      It forms a new bond with the carbocation
    • What does bromine water test for?
      Presence of carbon-carbon double bonds
    • What happens to the color of bromine water when it reacts with an alkene?
      It turns from orange to colorless
    • What are the key steps in the electrophilic addition mechanism of alkenes with bromine?
      1. Bromine approaches the alkene double bond.
      2. Electrons in bromine are repelled, creating partial charges.
      3. The partially positive bromine acts as an electrophile.
      4. A bond forms between bromine and one carbon atom.
      5. The double bond breaks, forming a carbocation.
      6. The bromide ion bonds with the carbocation.
      7. A di bromo alkane is formed.
    • What are the characteristics of electrophilic addition reactions?
      • Electrophiles are electron pair acceptors.
      • High electron density in double bonds attracts electrophiles.
      • Only one product is formed.
      • Both atoms from the electrophile are added to the alkene.
    • What is the significance of the bromine water test in organic chemistry?
      • Tests for unsaturation in molecules.
      • Color change indicates presence of double bonds.
      • Useful for confirming alkene presence.
    • How is a nucleophile defined?
      As an electron pair donor
    • What are the three electrophiles mentioned in the video?
      Bromine, hydrogen bromide, sulfuric acid
    • How does the mechanism of electrophilic addition start with bromine?
      Through induced dipole formation
    • What happens to the electrons in the bromine molecule during the reaction?
      They cause repulsion and create an induced dipole
    • What is formed after the first step of the electrophilic addition mechanism?
      An intermediate with a positive carbon
    • What is a carbocation?
      A positively charged carbon atom
    • What is the role of curly arrows in the mechanism?
      They show the movement of electrons
    • What is the first step in the electrophilic addition mechanism with bromine?
      Curly arrow from double bond to bromine
    • What is the significance of the positive charge on the carbocation?
      It indicates electron deficiency
    • What is the role of the lone pair on the bromine ion in the final step?
      It forms a bond with the carbocation
    • How does the addition of hydrogen bromide to ethane differ from bromine addition?
      Hydrogen bromide creates a permanent dipole.
    • What is positional isomerism in the context of propane and hydrogen bromide reaction?
      • Two different carbocations can form.
      • Leads to different products: 1-bromopropane and 2-bromopropane.