Addition of ammonium chloride to a solution containing ferric and magnesium ions is essential for selective precipitation of ferric hydroxide by aqueous ammonia.

True : Function of ammonium chloride is to suppress the ionization of NH base 4OH and thus check the precipitation of Mg(OH) base 2 because the solubility product of Mg(OH) base 2 is high.

This is used in salt analysis when 3^rd group radicals are precipitated. The group reagent are NH base 4OH in presence of NH base 4CI.