Calcium carbonate reacts with aqueous HCl to give CaCl2 and CO2 according to the reaction given below
CaCO3(s)+2HCl(aq)⟶CaCl2(aq)+CO2(g)+H2O(l)
What mass of CaCl2 will be formed when 250 mL of 0.76 M HCl reacts with 1000 g of CaCO3 ? Name the limiting reagent. Calculate the number of moles of CaCl2 formed in the reaction.
Molar mass of CaCO3=40+12+3×16=100 g mol−1
Moles of CaCO3 in 1000 g. nCaCO3=Mass (g)Molar mass
nCaCO3=1000 g100 g mol−1=10 molMolarity=Moles of solute (HCl)×1000Volumeofsolution
(It is given that moles of HCl in 250 mL of 0.76 M HCl=nHCl)
0.76=nHCl×1000250nHCl=0.76×2501000=0.19 mol.CaCO3(s)1 mol+2HCl(aq)2 mol⟶CaCl2(aq)+CO2(g)+H2O(l)
According to the equation,
1 mole of CaCO3 reacts with 2 moles HCl
∴ 10 moles of CaCO3 will react with 10×21 = 20 moles HCl.
But we have only 0.19 moles HCl, so HCl is limiting reagent and it limits the yield of CaCl2.
Since, 2 moles of HCl produces 1 mole of CaCl2
0.19 mole of HCl will produce 1×0.192=0.095 mol CaCl2
Molar mass of CaCl2=40+(2×35.5)=111g mol−1
∴ 0.095 mole of CaCl2=0.095×111=10.54g