Question

The drain cleaner, Drainex contains small bits of aluminum which react with caustic soda to produce dihydrogen. What volume of dihydrogen at ${20}^{o}C$ and one bar will be released when 0.15 g of aluminum reacts?

Answer 1

The reaction can be written as:-

$2A{l}_{\left(s\right)}+2NaO{H}_{\left(aq\right)}+2H_2{O}_{\left(l\right)}⟶{2NaAl{O}_2}_{\left(aq\right)}+{3H_2}_{\left(g\right)}$

Here, $2$ moles of $Al$ gives $3$ moles of $H_2$ gas.

Moles of aluminium= $\frac{0.15g}{27}=5.56\times {10}^{-3}$ moles

$\therefore$ Moles of $H_2$ produced= $\frac{3}{2}\times 5.56\times {10}^{-3}$

=$8.33\times {10}^{-3}$ moles

$\therefore$ Volume of $H_2$=$\frac{nRT}{P}$

=$\frac{8.33\times {10}^{-3}\times 0.0831\times 293}{1}$

=$0.203$ litres

$\therefore$ Volume of dihydrogen released is $0.203$ litres