Answer: 0.297 moles of calcium carbonate.
Solution:
Number of moles of HCl =[tex]\frac{\text{given mass}}{\text{molecular mass}}=\frac{21.9 g}{36.5 g/mol}=0.6[/tex] moles
[tex]CaCO_3+2HCl\rightarrow CaCl_2+H_2O+CO_2[/tex]
According to reaction
Two moles of HCl are reacting with one mole of [tex]CaCO_3[/tex], then 0.6 moles of HCl will react with:
=[tex]\frac{1}{2}\times 0.6\text{moles of}CaCO_3[/tex]
Moles of calcium carbonate reacted = 0.3 moles
In 0.3 moles of calcium carbonate 10% impurities is present i.e.
[tex]=0.3\times \frac{10}{100}=0.03 mol[/tex] of impurity.
Actual number of moles of calcium carbonate reacted = 0.3 - 0.003 = 0.297 moles.
