Mg + HCl -------> MgCl2 + H2
What volume of HCl is required from 27 % HCl to form 12.1 gram H2?
( D = 1.41 g/ml)
Balance the equation.
how many moles in 12.1g H2 ?
You'll need twice that many moles of HCl
So, how much 27% solution will have that many moles?