M5L2 - MP Quiz - Rates Graphs and Orders

Define the term electrophile.

• An electrophile is a species that accepts an electron pair to form a new covalent bond.

• An electrophile is a species that donates an electron pair to form a new covalent bond.

• An electrophile is a negatively charged ion that loses electrons easily.

• An electrophile is a molecule that always acts as a base in chemical reactions.

State reagents/conditions needed to turn an alkene to an alkane.

• Hydrogen gas (H2) and a nickel catalyst (Ni) at 150°C.

• Bromine water at room temperature.

• Concentrated sulfuric acid and heat.

• Aqueous potassium manganate(VII) at room temperature.

State the observations you would make when propene is bubbled through bromine water.

• The orange color of bromine water decolorizes.

• A white precipitate forms.

• The solution turns blue.

• Effervescence is observed.

Use structural formulae to write a balanced equation for the reaction that takes place when propene is bubbled through bromine water.

• CH2=CH-CH3 + Br2 → CH2Br-CHBr-CH3 (using structural formulae for each compound).

• CH3-CH2-CH3 + Br2 → CH2Br-CH2Br-CH3 (using structural formulae for each compound).

• CH2=CH2 + Br2 → CH2Br-CH2Br (using structural formulae for each compound).

• CH2=CH-CH3 + Br2 → CH2=CH-CH2Br + HBr (using structural formulae for each compound).

Draw a mechanism for the reaction of propene with bromine water.

• The mechanism is the electrophilic addition of Br2 to propene, showing the formation of a carbocation intermediate and the addition of Br- ion.

• The mechanism is a free radical substitution, where Br2 forms radicals and substitutes a hydrogen atom on propene.

• The mechanism is a nucleophilic substitution, where water attacks the double bond of propene directly.

• The mechanism is an elimination reaction, where Br2 removes a hydrogen and a bromine atom from propene to form an alkyne.

Draw the two products from the reaction of HBr with propene.

• 1-bromopropane and 2-bromopropane.

• 1-chloropropane and 2-chloropropane.

• 1-bromopropane and 3-bromopropane.

• 2-bromopropane and 3-bromopropane.

Predict the Major and Minor Products when HBr reacts with propene.

• Major product: 2-bromopropane; Minor product: 1-bromopropane.

• Major product: 1-bromopropane; Minor product: 2-bromopropane.

• Major product: 2-bromopropane; Minor product: 2-bromopropane.

• Major product: 1-bromopropane; Minor product: 1-bromopropane.

What factor determines the Major and minor product in the reaction of HBr with propene?

• Markovnikov's rule (the stability of the carbocation intermediate).

• The presence of sunlight.

• The boiling point of propene.

• The color of the reactants.

1. Electrophile: ________ [1]

• Electron pair acceptor

• Electron pair donor

• Proton donor

• Nucleophile

Alkene → Alkane reagents/conditions: ________

• H₂, Ni catalyst, 150ºC

• Br₂, CCl₄

• KMnO₄, H₂O, cold

• H₂SO₄, H₂O