66) Valency of Copper in Copper sulphate is

67) A _____ can resist pH change upon the addition of an acidic or basic component

68) Which is the smallest potential, which can produce electrolytic deposition when applied to an electrolytic cell.

69) The oxidation number of Aluminium in Aluminium metal is

70) Heavy metals are converted into its _____ for precipitation and separation in effluent treatment