69) The oxidation number of Aluminium in Aluminium metal is

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

71) Electro-forming of _____ is possible

72) Which is the elastic like force existing in surface of a body, especially a liquid tending to minimize the area of the surface.

73) If Gold is deposited on a surface of 200 square millimeter area, to an average thickness of 6 micrometer, the mass deposited Gold would be _____ mg. The specific gravity of Gold is 19.32.