Colours in Chemistry @dannnialftrii Ions Colour Gases Colour Copper Blue Hydrogen Colourless Iron (II) Green Oxygen Colourless Iron (III) Brown Carbon Dioxide Colourless Manganese (VII) Purple Ammonia Colourless Dichromate (VI) Orange Sulphur dioxide Colourless Bromine Colourless Hydrogen chloride Colourless Zinc Colourless Hydroxide Colourless Silver Colourless Nitrogen Dioxide Brown Chloride Colourless Bromine Brown Brown (Solution) Purple (Vapor) Yellowish green Solution Colour Iodine Magnesium Oxide White Chlorine Copper(II) Oxide Black Copper(II) Sulphate Blue Iron(II) Sulphate Green Zinc Sulphate Colourless Magnesium Sulphate Colourless Salt Colour (Solid) Colour (Solution) Salts for Ca2+, Mg2+, Al3+, Pb2+, NH4+ White Colourless CuSO4 & Cu(NO3)2 Blue Blue CuCl2 Green Blue FeSO4 / Fe(NO3)2 / FeCl2 Green Green Fe2(SO4)3 / Fe(NO3)3 / FeCl3 Brown Yellow / Brown CuCO3 Green Insoluble PbCl2 White Insoluble Salt Colour of Solution Cu2+ Blue Fe2+ Green Fe3+ Brown Indicator Colour in acidic solution Colour in neutral solution Colour in alkaline solution Litmus solution Red Purple Blue Methyl Orange Red Orange Yellow Methyl Red Red Orange Yellow Universal Indicator Red / Orange / Yellow Green Blue / Purple Phenolphtalein Colourless Colourless Pink