3.3 Halogenoalkanes Flashcards
General formula of halogenoalkanes
CₙH₂ₙX
(X = F,Cl, Br, I)
Functional group of halogeoalkanes
C-X
Why are halogenoalkanes more reactive than alkanes?
They have a polar bond
Uses of halogenoalkanes
- Refrigerants
- Solvents
- Pharmaceuticals
What order are halogens named in a halogenoalkane
Alphabetical order
Nucleophile
An electron pair donator
Why do halogenoalkanes have nucleophilic substitution reactions?
They have a polar carbon-halogen bond
What happens in a nucleophilic substitution reaction?
- Nucleophile donates electron pair to the δ+C atom
- This forms a new colvalent bond
- The C-X bond breaks
- Halide ion is formed
Product of the reaction between halogenoalkanes and aqueous hydroxides
Alcohols
What type of reaction is halogenoalkane + aqueous hydroxide?
Hydrolysis (the mechanism is nucleophilic substitution)
Conditions for hydrolysis of halogenoalkanes with aqueous hydroxides
- Warm
- Aqueous
Reagent for hydrolysis of halogenoalkanes with aqueous hydroxides
NaOH / KOH
General equation for hydrolysis of halogenoalkanes
RX + NaOH → ROH + NaX
R - hydrocarbon chain
X - halogen
Ethanolic
Solution in ethanol
Product of the reaction between halogenoalkanes and potassium cyanide
Nitriles
Conditions of the reaction between halogenoalkanes and potassium cyanide
- Warm
- Ethanolic
Nitrile group
C≡N
General equation for the reaction between halogenoalkanes and potassium cyanide
RX + KCN → RCN + KX
R - hydrocarbon chain
X - halogen
What effect does reacting halogenoalkanes with cyanide have on the carbon chain?
Increases the chain length
Mechanism for halogenoalkane + potassium cyanide
Nucleophilic substitution
