how many mililiters of a 0.4 molar HCl solution are needed to react completely with 13 grams of zinc according to the following equation?

Equation.
2 HCl + 1 Zn -----> 1 ZnCl2 + 1 H2

1 answer

13 g of Zn is 13/65.4 = 0.199 moles. You might as well round that off to 0.20 moles. You will require 0.4 moles of HCl for complete reaction.

That would be contained in 1 liter of a 0.4 molar solution.

One liter is 1000 ml.