HARD UNIT 4 - haloalkanes

Question 1

How do haloalkanes take part in elimination reactions?

Answer 1

They use a strong base, such as sodium or potassium hydroxide, in an ethanol solvent to form alkenes.

Question 2

What do haloalkanes take part in nucleophilic substitution reactions with?

Answer 2

aqueous alkalis to form alcohols.

ethanolic cyanide to form nitriles - can be hydrolysed to carboxylic acids.

alcoholic alkoxides to form ethers.

Question 3

What mechanisms do monohaloalkanes undergo nucleophilic substitution reactions by?

Answer 3

SN1 - One species in r.d.s. Occurs in a minimum of two steps via a trigonal planar carbocation intermediate.

SN2 - Two species in the r.d.s. Occurs in a single step via a five-centred, trigonal bipyramidal transition state.