Question

Find how many grams of zinc must be dissolved in dilute HCl to produce 300 cm${}^3$ of H${}_2$
$\text{Zn + HCl}\to {\text{ZnCl}}_{\text{2}}{\text{+ H}}_{\text{2}}$

Answer 1

Moles of $H_2=\frac{0.3}{22.4}=0.0134$

$Zn+HCl⟶ZnC{l}_2+H_2$

$1$ $mole$ $Zn$ produces $1$ $mole$ $H_2$

So, moles of $Zn$ reacted $=0.0134$

Now, molar mass of $Zn=65$

Mass $=0.0134\times 65=0.871$ $gm$