Question

3.2g of oxygen combines with 20g of a trivalent metal (M). The molecular mass of the sulphide of the metal is ??

Answer 1

Answer:

equivalent mass of metal=

(weight of metal / weight of oxygen) *8

20/3.2*8

50

since metal is trivalent

atomic mass = equivalent mass * 3

= 50*3

= 150

Answer 2

Answer:

396 g

Explanation:

3.2 g of oxygen = 20 g of x

so, 8 g of oxygen = 50 g of x

equivalent weight of x is 50 g.

as valency = 3, so atomic weight = 50 * 3

                              atomic weight = 150 g

formula = x₂s₃

molecular weight = x * 2 + s * 3

                             = 150 * 2 + 32 * 3

                             = 300 + 96

                             = 396 g

So, molecular mass of the sulphide of the metal x is 396 g.