When hydrogen gas was passed over 8.08 g of heated metal oxide, it was completely reduced and 1.8 g of water was formed :
(a) What is weight of oxygen in the metal oxide ?
(b) What is the equivalent mass of the metal ?

Explanation

(a) When hot metal oxide is treated with hydrogen, 1.8 g water if formed.
18 g `H_(2)O` contains 16 g oxygen.
(b) Equivalent mass may be defined as weight of the metal that combines with 8 parts of oxygen to from its oxide.
Mass of metal in its oxide = 8.08-1.6
=6.48 g
`because` 1.6 g oxygen combines with 6.48 g of metal
`therefore 8 g` oxygen will combine with `= (6.48)/(1.6)xx8` g of metal
=32.4 g
Thus, equivalent mass of metal =32.4