Answer to Question #2799 in Inorganic Chemistry for sadsen
How can I make the copper get white by salt or acit?
the metal copper is first converted to blue coloured copper sulphate by the
reaction with concentrated sulphuric acid.
Cu + H2SO4 --> CuSO4 (aq) (Blue)
the solution on evapourasion gives the Blue crystals of CuSO4*5H2O which on
further heating gives anhydrous CuSO4 which is colourless.
CuSO4*5H2O Blue --Heating --> CuSO4 white + 5H2O
Other method is the blue coppersulphate solution will react with ammonium
thiocyanate (NH4NCS) salt solution to give the white (colourless)
precipitate of copper thiocyanate Cu(NCS)2.