A 100% pure sample of a divalent metal carbonate weighing 2g on complete thermal decomposition releases `44 g c c` of carbon dioxide at STP. The equivalent mass of the metal is

Answer

20

Explanation

Divalent mettal carbonate means `MCO_(3)`
448 cc evolves from 2g
1 cc evolves from `2/448` g
22400 cc will evolve from `2/448 xx 22400` g = 100 g
i.e. 100 g is the molecular weights of the carbonate.
Then M.Wt of metal `=100 -(12 + 3 xx 16) = 40 g` (wt of carbonate, `CO_(3)^(2-)`)
Equivalent weight `=("Molecular weight")/("Valency") = 40/2 = 20`