In the equation Mg + 2HCl -> MgCl_2 + H_2, what volume of hydrogen at STP is produced from the reaction of 50.0 g of Mg and the equivalent of 75 g of HCl?

1 Answer
Feb 28, 2016

1.03 mol of dihydrogen gas will evolve, with a volume slightly over 22.4 dm^3 at STP.

Explanation:

Moles of magnesium: (50.0*g)/(24.31*g*mol^-1) = 2.06 mol

Moles of hydrogen chloride gas: (75.0*g)/(36.2*g*mol^-1) = 2.07 mol

Given equimolar amounts, clearly, the gas is in deficiency as the stoichiometric equation requires 2 equiv of gas per equiv of metal.

So, the 1 mole of gas evolves, (conveniently, as at STP the molar volume is 22.4 dm^3).