Question

Which of the following liberates methane on treatment with water?

• A. Silicon carbide
• B. Calcium carbide
• C. Beryllium carbide
• D. Magnesium carbide

Answer 1

The correct option is A Silicon carbide

The reaction between $SiC$ powder and $H_{2}O$ has been studied at ${400}^0-{800}^{0}C$ under 10 and 100MPa. Silicon carbide reacted with $H_{2}O$ to yield amorphous $Si{O}_2$ and $C{H}_4$ by the reaction,
$SiC+{2H}_{2}O⟶Si{O}_2+C{H}_4$ above ${500}^{0}C.$
The rate of oxidation of silicon carbide was studied at different partial pressures of water vapour. The diffusion‐rate constant was found to vary with the logarithm of the partial pressure of water vapour according to the theory of thin‐film oxidation as proposed by Engell and Hauffe. The products of oxidation were cristobalite and tridymite, depending on the temperature. The diffusing species appeared to be the same in the presence of partial pressures of water vapour and in the presence of partial pressures of oxygen.