Question

What volume of 0.57 M HCl is needed to react with 5.6 g CaCO3?

Answer 1

CaCO3 + 2HCl ==> CaCl2 + H2O + CO2

mols CaCO3 = grams/molar mass = ?
Using the coefficients in the balanced equation, convert mols CaCO3 to mols HCl.
Then M HCl = mols HCl/L HCl. YOu have mols and M, solve for L. (Convert to mL if desired.)