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 \(H_2\) = 2.02 g/mole
First we have to calculate the moles of HCl.
\(\text{Moles of HCl}=\frac{\text{Mass of HCl}}{\text{Molar mass of HCl}}=\frac{40g}{36.46g/mole}=1.097moles\)
Now we have to calculate the moles of hydrogen.
The balanced chemical reaction will be,
\(2HCl+Mg\rightarrow MgCl_2+H_2\)
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 \(\frac{1.097}{2}=0.5485\) mole of hydrogen
Now we have to calculate the mass of hydrogen.
\(\text{Mass of }H_2=\text{Moles of }H_2\times \text{Molar mass of }H_2\)
\(\text{Mass of }H_2=(0.5485moles)\times (2.02g/mole)=1.1079g=1.11g\)
Therefore, the theoretical yield of hydrogen is, 1.11 grams
