Iron reacts with HCl solution to give H2 gas and Fe2+ ions. Suppose that 3.6 g of iron are to be dissolved in 1.2 M HCl. What is the minimum volume (in mL) of the acid solution required to react with all of the iron?

Answer 1

Fe + 2HCl ==> FeCl2 + H2
mols Fe = grams/molar mass = approx 0,06 but you need a better answer than that.
Convert to mols HCl which will be twice mols Fe and you get that from the coefficients in the balanced equation. Then M HCl = mols HCl/L HCl. You have M and mols, solve for L and convert to mL.