Question

A metal carbonate (0.5 kg) gives 0.28 kg of its
oxide on heating. Hence, the equivalent weight of
metal is​

Answer 1

Let valency of metal of atomic mass, M is x. now chemical formula of metal carbonate is $M_2(CO_3)_x$

a/c to question,

0.5kg of metal carbonate gives 0.28kg of its oxide on heating.

$M_2(CO_3)_x\rightarrow M_2O_x+xCO_2$

here it is clear that, 1 mole of metal carbonate produced 1 mole of metal oxide.

so, mass of metal carbonate/molar mass of metal carbonate = mass of metal oxide/molar mass of metal oxide

or, 500g/(2M + 60x) = 280g/(2M + 16x)

or, 25(2M + 16x) = 14(2M + 60x)

or, 50M + 400x = 28M + 840x

or, 22M = 440x

or, M/x = 440/22 = 20

we know, equivalent weight is atomic mass by valency.

so, equivalent mass = M/x = 20