Haloalkanes

• Hydrolysis is the breaking of a bond by its reaction with water.
• A nucleophile is a species attracted to an electron deficient centre where it donates a pair of electrons to form a new covalent bond.
• Electronegativity is the ability of an atom to attract the bonding electrons towards itself in a covalent bond.
• Homologous series - a series of organic compounds having the same functional group but with each successive member differing by CH2.
• Alkyl halides are also known as haloalkanes
• Functional group - a group of atoms responsible for the characteristic reactions of a compound.
• Saturated - single bonds only.
• Unsaturated - containing one or more double bonds between carbon atoms.
• Curly arrows indicate the movement of an electron pair, showing either the breaking or formation of a covalent bond.
• A radical is a species with an unpaired electron.
• Homolytic fission is the breaking of a covalent bond where the shared pair of electrons are split equally, forming two radicals.
• Heterolytic fission is the breaking of a covalent bond where the shared pair of electrons are not split equally, forming a cation and an anion.
• Bond enthalpy is the average enthalpy change that takes place when breaking 1 mol of a given type of bond in the molecules of a gaseous species.
• Bond polarity is the polarity that arises in a covalent bond due to the difference in the electronegativities of the atoms in the bond.
• Substitution is a chemical reaction in which an atom (or group of atoms) in a reactant molecule is replaced by a different atom (or group of atoms).
• Electron deficient is an atom with a slight positive charge due to a covalent bond with a more electronegative atom.
• Reflux is the continuous boiling and condensing of a reaction mixture to ensure the reaction takes place but prevents the contents of the flask boiling dry.
• Volatility is the ease with which a liquid turns into a gas.
• When naming a haloalkane, the halogen has the lowest priority.
• If the carbon attached to the halogen has only 1 other carbon attached, it is primary.
• If the carbon attached to the halogen has 2 other carbons attached, it is secondary.
• If the carbon attached to the halogen has 3 other carbons attached, it is tertiary.
• If the halogen is Fluorine, the prefix is Fluoro-.
• If the halogen is Chlorine, the prefix is Chloro-.
• If the halogen is Bromine, the prefix is Bromo-.
• If the halogen is Iodine, the prefix is Iodo-.
• If there is more than one group branching from the main chain then they will be named alphabetically.
• Haloalkanes can also be called halogenoalkanes.
• Haloalkanes are organic compounds in which a halogen atom has replaced at least one of the hydrogen atoms in an alkane chain.
• If there are two halogens attached, the prefix di- is used.
• If there are three halogens attached, the prefix tri- is used.
• If there are four halogens attached, the prefix tetra- is used.
• Haloalkanes are much more reactive than alkanes due to the presence of the electronegative halogens.
• The carbon-halogen bond is polar, causing the carbon to carry a partial positive and the halogen a partial negative charge.
• Due to the large difference in electronegativity between the carbon and halogen atom, the C-X bond is polar.
• Because the C-X bond is polar, haloalkanes will undergo substitution reactions.
• Nucleophilic Substitution Reactions: -

  • A halogen is substituted for another atom or group of atoms.
  • The products formed when haloalkanes undergo this type of reaction are alcohols, amines, and nitriles.
• Examples of nucleophiles include: -

  • Hydroxide ions
  • Water molecules
  • Ammonia molecules
  • Cyanide
• All of the halogens are much more electronegative than carbon. This means that the C-X bond is polar. The carbon atom is electron deficient.
• A nucleophile is a species that will donate an electron pair to form a covalent bond.