1.35 Calcium carbonate reacts with aqueous HCl to give CaCl2 and CO2 according to the reaction, CaCO3 (s) + 2 HCl (aq) CaCl2 (aq) + CO2(g) + H2O(l)

What mass of CaCO3 is required to react completely with 25 mL of 0.75 M HCl?

NEETprep answer:  

0.75 M of HCl ≡ 0.75 mol of HCl are present in 1 L of water

≡ 27.375 g of HCl is present in 1 L of water

Thus, 1000 mL of solution contains 27.375 g of HCl.
 Amount of HCl present in 25 mL of solution
27.375g1000 mL x 25 mL
= 0.6844 g
From the given chemical equation,
CaCO3s + HClaq  CaCl2aq + CO2g + H2Ol

   71 g HCl react with  of 100 g CaCO3 .
Amount of CaCO3 that will react with 0.6844 g = 10071  0.6844 g
= 0.9639 g