A mixture contains Na2CO3 and NaHCO3 and wt. of mixture is 10gm. Mixture on heating liberates 56ml of CO2 at S.T.P, wt of Na2CO3 in mixture is
Only NaHCO3 evolve CO2 gas. Na2CO3 does not evolve CO2 gas even on red heating.
So, the only reaction happening is:
2NaHCO3 -> Na2CO3 + CO2 + H2O
Weight:
2(23+1+12+16*3) -> (2*23+12+16*3) + (12+16*2) + (1*2+16)
168g -> 102g + 44g + 18g
Also, CO2 mass as per 56ml volume obtained at STP = 56/(22.4 * 1000) * (44) = 0.11g
So, NaHCO3 weight = 0.11/44*168 = 0.42g (using ratio of weights from equation)
Therefore, original Na2CO3 weight in the original mixture = 10 - 0.42 = 9.58g