Alkenes and Alkynes Hydrogenation, Halogenation, Halohydrin, Oxymercuration, Hydroboration

Concept Summary

• Hydrogenation is a chemical reaction where hydrogen is added to a molecule, often resulting in the saturation of unsaturated bonds.
• Halogenation is a chemical reaction where a halogen is added to a molecule, often resulting in the substitution of a hydrogen atom with a halogen atom.
• Halohydrin formation is a type of halogenation reaction where a halogen and a water molecule are added to an alkene, resulting in the formation of a halohydrin.
• Oxymercuration is a chemical reaction where a mercury compound and a water molecule are added to an alkene, resulting in the formation of an alcohol.
• Hydroboration is a chemical reaction where a borane and a water molecule are added to an alkene, resulting in the formation of an alcohol.

Questions

WHAT (definitional)

• Q1: What is hydrogenation?
• Answer: Hydrogenation is a chemical reaction where hydrogen is added to a molecule, often resulting in the saturation of unsaturated bonds.
• Real-world example: The hydrogenation of vegetable oils to produce margarine.
• Misconception cleared: Hydrogenation is not the same as hydration, which involves the addition of a water molecule.
• Q2: What is halogenation?
• Answer: Halogenation is a chemical reaction where a halogen is added to a molecule, often resulting in the substitution of a hydrogen atom with a halogen atom.
• Real-world example: The chlorination of drinking water to disinfect it.
• Misconception cleared: Halogenation is not the same as halogenation of an alkene, which involves the addition of a halogen to an alkene.
• Q3: What is oxymercuration?
• Answer: Oxymercuration is a chemical reaction where a mercury compound and a water molecule are added to an alkene, resulting in the formation of an alcohol.
• Real-world example: The oxymercuration of alkenes to produce alcohols in the synthesis of certain pharmaceuticals.
• Misconception cleared: Oxymercuration is not the same as hydroboration, which involves the addition of a borane to an alkene.

WHY (causal reasoning)

• Q1: Why is hydrogenation used to produce margarine?
• Answer: Hydrogenation is used to produce margarine because it allows for the saturation of unsaturated bonds in vegetable oils, resulting in a more solid and stable product.
• Real-world example: The hydrogenation of soybean oil to produce a solid margarine.
• Misconception cleared: Hydrogenation is not used to produce margarine because it is a cheap process, but rather because it results in a more stable and solid product.
• Q2: Why is halogenation used to disinfect drinking water?
• Answer: Halogenation is used to disinfect drinking water because it is an effective method for killing bacteria and other microorganisms.
• Real-world example: The chlorination of drinking water to disinfect it and prevent the spread of waterborne diseases.
• Misconception cleared: Halogenation is not used to disinfect drinking water because it is a toxic process, but rather because it is an effective method for killing bacteria and other microorganisms.
• Q3: Why is oxymercuration used to produce alcohols?
• Answer: Oxymercuration is used to produce alcohols because it is a highly regioselective reaction, resulting in the formation of a single alcohol product.
• Real-world example: The oxymercuration of alkenes to produce alcohols in the synthesis of certain pharmaceuticals.
• Misconception cleared: Oxymercuration is not used to produce alcohols because it is a difficult process, but rather because it is a highly regioselective reaction.

HOW (process/application)

• Q1: How is hydrogenation carried out?
• Answer: Hydrogenation is carried out by adding hydrogen gas to a molecule in the presence of a catalyst, such as palladium or platinum.
• Real-world example: The hydrogenation of vegetable oils to produce margarine using a palladium catalyst.
• Misconception cleared: Hydrogenation is not carried out by simply adding hydrogen gas to a molecule, but rather by using a catalyst to facilitate the reaction.
• Q2: How is halogenation carried out?
• Answer: Halogenation is carried out by adding a halogen to a molecule in the presence of a catalyst, such as light or heat.
• Real-world example: The chlorination of drinking water to disinfect it using chlorine gas.
• Misconception cleared: Halogenation is not carried out by simply adding a halogen to a molecule, but rather by using a catalyst to facilitate the reaction.
• Q3: How is oxymercuration carried out?
• Answer: Oxymercuration is carried out by adding a mercury compound to an alkene in the presence of water.
• Real-world example: The oxymercuration of alkenes to produce alcohols in the synthesis of certain pharmaceuticals.
• Misconception cleared: Oxymercuration is not carried out by simply adding a mercury compound to an alkene, but rather by using water to facilitate the reaction.

CAN (possibility/conditions)

• Q1: Can hydrogenation be carried out on any molecule?
• Answer: No, hydrogenation can only be carried out on molecules that have unsaturated bonds.
• Real-world example: The hydrogenation of vegetable oils to produce margarine, which requires the presence of unsaturated bonds.
• Misconception cleared: Hydrogenation is not a universal reaction that can be carried out on any molecule, but rather requires the presence of unsaturated bonds.
• Q2: Can halogenation be carried out on any molecule?
• Answer: No, halogenation can only be carried out on molecules that have hydrogen atoms that can be substituted with a halogen.
• Real-world example: The chlorination of drinking water to disinfect it, which requires the presence of hydrogen atoms.
• Misconception cleared: Halogenation is not a universal reaction that can be carried out on any molecule, but rather requires the presence of hydrogen atoms that can be substituted with a halogen.
• Q3: Can oxymercuration be carried out on any alkene?
• Answer: No, oxymercuration can only be carried out on alkenes that have a certain level of reactivity.
• Real-world example: The oxymercuration of alkenes to produce alcohols in the synthesis of certain pharmaceuticals, which requires the presence of a reactive alkene.
• Misconception cleared: Oxymercuration is not a universal reaction that can be carried out on any alkene, but rather requires the presence of a reactive alkene.

TRUE/FALSE (misconception testing)

• Q1: Hydrogenation is a reversible reaction.
• Answer: FALSE
• Real-world example: The hydrogenation of vegetable oils to produce margarine, which is an irreversible reaction.
• Misconception cleared: Hydrogenation is not a reversible reaction, but rather an irreversible process that results in the saturation of unsaturated bonds.
• Q2: Halogenation is a highly regioselective reaction.
• Answer: FALSE
• Real-world example: The chlorination of drinking water to disinfect it, which is not a highly regioselective reaction.
• Misconception cleared: Halogenation is not a highly regioselective reaction, but rather a reaction that can result in the formation of multiple products.
• Q3: Oxymercuration is a highly toxic reaction.
• Answer: FALSE
• Real-world example: The oxymercuration of alkenes to produce alcohols in the synthesis of certain pharmaceuticals, which is a relatively safe reaction.
• Misconception cleared: Oxymercuration is not a highly toxic reaction, but rather a relatively safe process that can be carried out in a laboratory setting.