GCSE Chemistry - Addition Reactions of Alkenes #55

The video tutorial explains the reactions of alkenes, which are unsaturated hydrocarbons with carbon-carbon double bonds. These double bonds allow alkenes to undergo addition reactions with hydrogen, water, and halogens. The video covers hydrogenation, where alkenes react with hydrogen to form alkanes, hydration, where alkenes react with water to form alcohols like ethanol, and halogenation, where alkenes react with halogens such as bromine. The tutorial also discusses the separation of reaction products using fractional distillation and the use of bromine as a test to distinguish alkenes from alkanes.

What characteristic of alkenes allows them to undergo addition reactions?

• Presence of a carbon-carbon double bond

• Presence of a carbon-nitrogen triple bond

• Presence of a carbon-oxygen double bond

• Presence of a carbon-carbon single bond

What is the product formed when propane reacts with hydrogen?

• Propene

• Propane

• Butane

• Ethane

Which condition is necessary for the reaction of ethene with water to form ethanol?

• Presence of sunlight

• Low temperature

• Presence of a catalyst and high temperature

• Absence of a catalyst

What is the main method used to separate ethanol from water after the reaction with ethene?

• Decantation

• Fractional distillation

• Filtration

• Simple distillation

What is the color change observed when bromine reacts with an alkene?

• Color changes from red to yellow

• Color changes from blue to green

• Color changes from colorless to orange

• Color changes from orange to colorless

Why do alkanes not react with bromine in the same way as alkenes?

• Alkanes have triple bonds

• Alkanes have double bonds

• Alkanes are saturated and lack double bonds

• Alkanes are unsaturated

Which of the following is a test to distinguish alkenes from alkanes?

• Reaction with water

• Reaction with hydrogen

• Reaction with bromine

• Reaction with oxygen