Some general observations can be made during acid reactions:
It is useful to know the colour of some compounds commonly reacted with acids to work out if a colour change has occurred.
|copper(II) oxide||black solid|
|copper(II) carbonate||green solid|
|hydrated copper(II) sulfate||blue crystals|
|copper(II) salts in solution||blue solution|
|group 1, group 2, aluminium and zinc compounds||white solids – if they dissolve in water they give colourless solutions|