$10 \mathrm{~g}$ of hydrogen and $64 \mathrm{~g}$ of oxygen were filled in a steel vessel and exploded.…

$10 \mathrm{~g}$ of hydrogen and $64 \mathrm{~g}$ of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be -
  1. $1 \mathrm{~mol}$
  2. $2 \mathrm{~mol}$
  3. $3 \mathrm{~mol}$
  4. $4 \mathrm{~mol}$

Solution

$\mathrm{H}_2+1 / 2 \mathrm{O}_2 \rightarrow \mathrm{H}_2 \mathrm{O}$ $2 \mathrm{~g} \quad 16 \mathrm{~g} \quad 18 \mathrm{~g}$ $10 \mathrm{~g} \mathrm{H}_2$ required $\mathrm{O}_2=80$ which is not present 64 g $\mathrm{O}_2$ required $8 \mathrm{~g}$ of $\mathrm{H}_2$ and $\mathrm{H}_2$ left $=2 \mathrm{~g}$. Thus, $\mathrm{O}_2$ is the limiting reactant and $\mathrm{H}_2$ is excess reactant. Hence, $\mathrm{H}_2 \mathrm{O}$ formed from 64 of $\mathrm{O}_2$ $\begin{aligned} & =\frac{18}{16} \times 64 \\ & =72 \mathrm{~g}=\frac{72}{18} \mathrm{~mole} \\ & =4 \mathrm{~mole} \end{aligned}$

Asked in: NEET 2009 (Mains)

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