Solutions of chromium(VI) that contain an excess of chloride ions can be determined by direct titration with ammonium iron(II) sulphate, with either N-phenylanthranilic acid or diphenylamine-4-sulphonic acid as indicator. Solutions of chromium(III) that contain an excess of chloride ions can be determined similarly after oxidising the chromium(III) to chromium(VI) with alkaline hydrogen peroxide.