If 40.0 g of hcl react with an excess of magnesium metal, what is the theoretical yield of hydrogen?
a. 1.11 g
b. 2.22 g
c. 52.2 g
d. 104 g

Answer : The theoretical yield of hydrogen is, 1.11 grams

Solution : Given,

Mass of HCl = 40 g

Molar mass of HCl = 36.46 g/mole

Molar mass of = 2.02 g/mole

First we have to calculate the moles of HCl.

Now we have to calculate the moles of hydrogen.

The balanced chemical reaction will be,

From the balanced reaction we conclude that,

2 moles of HCl react to give 1 mole of hydrogen

1.097 moles of HCl react to give mole of hydrogen

Now we have to calculate the mass of hydrogen.

Therefore, the theoretical yield of hydrogen is, 1.11 grams