Summary
Organic chemistry involves understanding various types of reactions and mechanisms, including how bonds break and form.
- Nucleophile — an atom or molecule that donates electrons to form new bonds. Example: Hydroxide ions (OH-), ammonia (NH3), and water (H2O) are common nucleophiles.
- Addition Reaction — involves the formation of a new covalent bond between an electrophile and a nucleophile. Example: Reaction of an alkene with hydrogen gas to form an alkane.
- Substitution Reaction — involves the replacement of one functional group or atom with another. Example: Reaction of a haloalkane with a nucleophile to form an alkyl nucleophile and a halide ion.
- Elimination Reaction — involves the removal of a functional group to form a new double bond. Example: Reaction of an alcohol with a strong acid to form an alkene.
- Hydrolysis — involves the cleavage of a chemical bond using water. Example: Hydrolysis of an ester to produce a carboxylic acid and an alcohol.
- Condensation Reaction — involves the formation of a new bond with the loss of a small molecule. Example: Reaction between a carboxylic acid and an alcohol to form an ester.
- Oxidation and Reduction — involves changes in the number of bonds to oxygen or hydrogen. Example: Oxidation of a primary alcohol to an aldehyde.
- Homolytic Fission — bond breaking that results in two free radicals. Example: Not explicitly provided.
- Heterolytic Fission — bond breaking that results in a cation and an anion. Example: Dissolution of hydrogen chloride in water to form H+ and Cl- ions.
Exam Tips
Key Definitions to Remember
- Nucleophile
- Addition Reaction
- Substitution Reaction
- Elimination Reaction
- Hydrolysis
- Condensation Reaction
- Oxidation and Reduction
- Homolytic Fission
- Heterolytic Fission
Common Confusions
- Confusing nucleophiles with electrophiles
- Mixing up addition and substitution reactions
- Misunderstanding the difference between homolytic and heterolytic fission
Typical Exam Questions
- What is a nucleophile? A nucleophile is an atom or molecule that donates electrons to form new bonds.
- Describe an addition reaction. An addition reaction involves the formation of a new covalent bond between an electrophile and a nucleophile.
- What happens during hydrolysis? Hydrolysis involves the cleavage of a chemical bond using water.
What Examiners Usually Test
- Understanding of reaction mechanisms
- Ability to identify types of reactions
- Knowledge of bond fission processes
