Chemistry of the haloalkanes Flashcards
What are haloalkanes?
Compounds containing the elements carbon, hydrogen, and at least one halogen.
How are haloalkanes named?
A prefix is added to the name of the longest chain to indicate the identity of the halogen.
What are the classifications of haloalkanes based on the carbon chain?
- Primary
- Secondary
- Tertiary
What are the prefixes used to represent the different halogens in haloalkanes?
- F - fluoro-
- Cl - chloro-
- Br - bromo-
- I - iodo-
What type of bond do haloalkanes contain?
A carbon-halogen bond.
What is the charge of the carbon atom in a carbon-halogen bond?
Slightly positive.
What is a nucleophile?
An atom or group of atoms that is attracted to an electron deficient carbon atom and donates a pair of electrons.
Which species are considered nucleophiles?
- Hydroxide ions (OH⁻)
- Water molecules (H₂O)
- Ammonia molecules (NH₃)
What is nucleophilic substitution?
A reaction in which one atom or group of atoms is replaced by another atom or group of atoms.
What happens during the hydrolysis of a haloalkane?
The halogen atom is replaced by an —OH group.
What is the first step in the hydrolysis of a haloalkane?
The nucleophile, OH⁻, approaches the carbon atom attached to the halogen from the opposite side.
What does the direction of attack by the OH⁻ ion minimize?
Repulsion between the nucleophile and the halogen atom.
What is produced from the hydrolysis of 1-bromobutane?
Butan-1-ol and NaBr.
What factors affect the rate of hydrolysis of haloalkanes?
The strength of the carbon-halogen bond.
Which carbon-halogen bond is the strongest?
C-F bond.
Which carbon-halogen bond is the weakest?
C-I bond.
Predict the reactivity order of haloalkanes based on bond strength.
- Iodoalkanes react faster than bromoalkanes
- Bromoalkanes react faster than chloroalkanes
- Fluoroalkanes are unreactive.
What is the general equation for the hydrolysis of haloalkanes?
CH₃CH₂CH₂CH₃X + H₂O —> CH₃CH₂CH₂CH₃OH + H⁺ + X⁻.
How can the rate of hydrolysis of haloalkanes be measured?
By carrying out the reaction in the presence of aqueous silver nitrate.
What forms when halide ions react with Ag⁺ ions?
A precipitate of silver halide.
What is the role of ethanol in the hydrolysis reaction of haloalkanes?
It allows water and the haloalkane to mix and produce a single solution.
Which haloalkane reacts slowest in hydrolysis?
1-Chlorobutane.
Which haloalkane reacts fastest in hydrolysis?
1-Iodobutane.
