How would we differentiate calcium chloride, and copper sulfate?

1 Answer
Apr 23, 2016

Dissolve a bit of both powders in water. #CuSO_4# will give a beautiful blue colour.


#CuSO_4# is a white solid (a residue of water will probably give a faint blue colouration). Dissolution in water gives #[Cu(OH_2)_6]^(2+)#, which gives a characteristic blue colour in solution; this is truly one of the most beautiful colours you can see.

On the other hand, calcium chloride, a pure white powder (or colourless crystals) will give a colourless solution. Why the difference in colour? #Cu^(2+)# possesses #d# electrons, whose transitions give rise to the colour.