No. of moles of CaCO3=Mw=1001=0.01mol [∵ Molar mass of CaCO3=100gmol−1] 100mL of N/5HCl=1000100×51 =0.02mol
The reaction is represented as : CaCO3+2HCl⟶CaCl2+CO2+H2O 1 mole of CaCO3 reacts with 2 moles of HCl.
Hence, 0.01 mole of CaCO3 will react completely with 0.02 mole of HCl.