Question

Zinc and hydrochloric acid react according to the following reaction :

$Zn\left(s\right)+ \, 2HCl \, \left(a q .\right) \rightarrow ZnCl_{2}\left(\right.aq.\left.\right)+H_{2}\left(\right.g\left.\right)$

If $0.30 \, mole \, of \, Zn is$ added to $0.52 \, mole \, HCl,$ how many moles of $H_{2}$ is produced?

• A. $0.2$
• B. $0.62$
• C. $0.6$
• D. $0.26$

Answer 1

Answer: (D)

$\because \, Mole \, ratio \, of \, Zn:HCl:H_{2} \, is \, 1:2:1$

$2 \, \, \text{mole} \, \, \text{HCl} \, \, \text{gives} = 1 \, \, \text{mole} \, \text{H}_{\text{2}}$

$0.52 \, \, \text{mole} \, \, \text{HCl} \, \, \text{gives}=\frac{1 \times 0.52}{2}=0.26 \, \, \text{mole}$

Note that $HCl$ is used completely and thus it is limiting reagent.