SOLUTIONS TO TEXT PROBLEMS 8.1 Identify the nucleophilic anion in each reactant. The nucleophilic anion replaces bromine as a sub- stituent on carbon. (b) Potassium ethoxide serves as a source of the nucleophilic anion CH,CH,. CH,CH,: CH, Br: CH3CH2OCH3 + Br: Ethoxide ion Methyl bromide Ethyl methyl ether Bromide ion