JAMB - Chemistry (1989 - No. 41)
In the above set up substances X and Y are respectively
lime water copper (ll) tetraoxosulphate (lV)
potassium trioxocarbonate and alkaline pyrogallol
potassium hydroxide and alkaline pyrogallol
potassium trioxocarbonate (lV) and concentrated tetraoxosulphate (IV) acid