Nucleophilic substitution in halogenoalkanesAQA A-Level Chemistry: Mind map

Exam questions on Nucleophilic substitution in halogenoalkanes

1. 1-Bromobutane, CH₃CH₂CH₂CH₂Br, is warmed with aqueous sodium hydroxide, NaOH. Butan-1-ol is formed by a nucleophilic substitution reaction.
   Write an equation for the reaction of 1-bromobutane with hydroxide ions.2 marks
2. A chemist converts 1-bromopropane, CH₃CH₂CH₂Br, into butanenitrile, CH₃CH₂CH₂CN, by heating it under reflux with a solution of potassium cyanide, KCN, in ethanol.
   Suggest why this reaction is useful in organic synthesis.2 marks
3. A student compares the rates of reaction of three halogenoalkanes with water. Each of 1-chlorobutane, 1-bromobutane and 1-iodobutane is warmed with aqueous silver nitrate in ethanol and the time taken for a precipitate of the silver halide to form is measured. The bond enthalpies are: C–Cl 338 kJ mol⁻¹, C–Br 276 kJ mol⁻¹ and C–I 238 kJ mol⁻¹.
   Predict which halogenoalkane forms a precipitate first and explain your answer.3 marks