Aluminum carbide (Al₄C₃) liberates methane on treatment with water. The grams of aluminum carbide required to produce 11.2 L of methane under STP conditions is:

Balanced chemical reaction is:

${\mathrm{Al}}_4{\mathrm{C}}_3+12{\mathrm{H}}_2\mathrm{O}\to 3{\mathrm{CH}}_4+4\mathrm{Al}{\left(\mathrm{OH}\right)}_3$

144 g of Al₄C₃ liberates 67.2 L of methane. Mass of Al₄C₃ requires to liberate 11.2 L of methane is:

$\mathrm{Mass} \mathrm{of} {\mathrm{Al}}_2{\mathrm{C}}_3=\frac{144 \mathrm{g}}{67.2 \mathrm{L}}\times 11.2 \mathrm{L}=24 \mathrm{g}$