Laboratory test of haloalkanes

Haloalkanes are of neutral character in aqueous medium -- they do not turn litmus, for instance. On warming a haloalkane with aqueous sodium or potassium hydroxide, the covalently bonded halogen atom is converted into a free halide ion: R-X + OH- (heat) -> R-OH + X-. The resulting reaction mixture is then acidified by adding dilute nitric acid (which destroys any excess hydroxide that would otherwise interfere by also precipitating silver hydroxide/oxide), and silver nitrate solution is added; a precipitate of the corresponding silver halide forms, Ag+(aq) + X-(aq) -> AgX(down-arrow)(s), and this precipitate is what confirms the presence of halogen in the original organic compound. In practice the colour and behaviour of the precipitate (white AgCl that dissolves in dilute ammonia, pale yellow AgBr that dissolves only in concentrated ammonia, yellow AgI that is insoluble even in concentrated ammonia) can further indicate which halogen was present, though …