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What volume of gas is evolved at S.t.p if 2g of calcium t...

What volume of gas is evolved at S.t.p if 2g of calcium trioxocarbonate (IV) is added to a solution of hydrochloric acid?
[Ca = 40, C = 12, O = 16, Cl = 35.5, H = 1 Molar volume of agas at s.t.p = 22.4 dm3

A.

112 cm2

B.

224 cm2

C.

448 cm2

D.

2240 cm2

Correct answer is C

CaCO3(s) + 2HCl(aq) → CaCl2 + H2O(l) + CO2


The relative molecular mass of CaCO3 = 40 + 12 + 16 * 3 = 52 +48 = 100 ;

Relative molecular mass of CO2 = 12 + 10 * 2 = 44


From the above equation, 100g of CaCO3reacts with 44g of CO2 at s.t.p. i.e 22.4 dm3


2g of CaCO3 will react with (2*22.4)/100 of CO2 = 0.448 dm3


0.448 dm3 = 0.448 * 1000 = 448cm3