19 g of a mixture containing `NaHCO_(3)` and `Na_(2)CO_(3)`, on complete heating liberated 1.12 L of `CO_(2)` at STP. The weight of the remaining solid was 15.9 g. What is the weight (in g) of `Na_(2)CO_(3)`, in the mixture before heating?

Options

A. 8.4
B. 15.9
C. 4
D. 10.6

Answer

(d)

Explanation

Molecular weight of `NaHCO_(3)`= 84
Molecular weight of `Na_(2)CO_(3)`= 106
`:.` Total weight of the mixture `= 84 + 106 = 190`
190g of mixture contains 106g of `Na_(2)CO_(3)`
`:.` 19g of mixture contains x g of `Na_(2)CO_(3)`
`rArr x = (19 xx 106)/190 `
x = 10.6g.