Question

What happens when steam is passed over red hot iron? Write the equation.

Answer 1

Upon passing steam over red-hot iron, the formation of iron oxide occurs with the passage of hydrogen gas (H₂).

Equation:

• $3\mathrm{Fe}\left(\mathrm{s}\right)+4{\mathrm{H}}_2\mathrm{O}\left(\mathrm{aq}\right)\to {\mathrm{Fe}}_3{\mathrm{O}}_4\left(\mathrm{s}\right)+4{\mathrm{H}}_2\left(\mathrm{g}\right)$
• The reaction shows that when 3 molecules of iron $\left(\mathrm{Fe}\right)$ react with 4 molecules of water$\left({\mathrm{H}}_2\mathrm{O}\right)$, the magnetic oxide $\left({\mathrm{Fe}}_3{\mathrm{O}}_4\right)$ is formed with the release of 4 molecules of hydrogen$\left({\mathrm{H}}_2\right)$.
• This reaction only proceeds if iron is red hot, as iron is not that reactive at ordinary from (room temperature).
• Hence, it is a property of alkali metals to react with to produce hydrogen gas, but iron being moderately reactive does not react with water at room temperature, therefore heat must be supplied.