Question

What is the equivalent weight of hydride of metal if equivalent weight of its oxide is 20

Answer 1

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.

thank you.

Answer 2

E+8=20
E=12
equivalent weight of hydride=E+1
=12+1
=13