Question

Equivalent mass of a metal is 12gmol^1 . Hence equivalent mass of its oxide is

Answer 1

Equivalent mass of a metal is the  mass of  metal that combines with 8 gms of oxygen to form a compound.

So equivalent mass of the metal  is  12  +  8  = 20.

I think it is supposed to be a number...  no units  like  g/mol ..

equivalent mass  of an element  =  atomic mass / valency

equivalent mass of the compound =  molecular mass / valency of metal in the compound

So  the metal is probably  Magnesium : Ms with Z = 12, and Mass = 24.  Valency = 12.
        Magnesium Oxide = Mg O.

Answer 2

Unit of equivalent mass is same as that of mass. It can also be written as 'gram per equivalent' or g/eq.

Equivalent mass of metal = 12g
equivalent mass of oxygen = 16/2 = 8g
equivalent mass of oxide = 12+8 = 20g

So equivalent mass of the oxide is 20g.