Question

If the quantity of metal in a metallic oxide is 60%, then its equivalent weight is:

1. 1/5 of molecular weight
2. 3/2 of molecular weight
3. 3/5 of molecular weight
4. 1/2 of molecular weight

Answer 1

quantity of metal in metallic oxide is 60%
Let atomic mass of metal is M
we know, atomic mass of oxygen is 16 g/mol

so, molecular mass of Metallic oxide = 2M + 16n , where n is valency of metal
so, 2M/(2M + 16n) × 100 = 60
2M × 5 = 3(2M + 16n)
10M = 6M + 48n
4M = 48n
M = 12n
M/n = 12 .....(1)
hence, equivalent mass of metal = 12

so, equivalent weight = equivalent weight of metal + equivalent weight of oxygen
= 12 + 8 = 20

now, molecular weight = (2M + 16n)
and equivalent weight = 20
from equation (1), if we assume m = 12 and n = 1
then, (2M + 16n) = 40 and equivalent weight = 20
so, equivalent weight is 1/2 of molecular weight
hence option (4) is correct

Answer 2

Answer:

Let the atomic weight of metal be ëxí x 60

x  16  100  x = 24, therefore the metal is Magnesium (Mg)

Molecular weight of metal oxide Charge on cation

Equivalent weight 

So, Equivalent weight of Magnesium Oxide 

2+

Molecular weight 2