Question

________gas is evolved when Zinc granules are treated with Sodium hydroxide.

• A. Oxygen
• B. Hydrogen
• C. Sodium oxide
• D. Hydrogen oxide

Answer 1

The correct option is B

Hydrogen

The explanation for the correct option (B):

• The reaction between metal and a base leads to the formation of salt along with Hydrogen gas (${\mathrm{H}}_2$).
• When Sodium hydroxide ($\mathrm{NaOH}$) reacts with Zinc ($\mathrm{Zn}$), then a salt, Sodium zincate (${\mathrm{Na}}_2{\mathrm{ZnO}}_2$) is formed along with the liberation of ${\mathrm{H}}_2$ gas.
• $2\mathrm{NaOH}\left(\mathrm{aq}\right)+\mathrm{Zn}\left(\mathrm{s}\right)\stackrel{∆}{\to }{\mathrm{Na}}_2{\mathrm{ZnO}}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$
• Hence, ${\mathrm{H}}_2$ gas is evolved when $\mathrm{Zn}$ is treated with $\mathrm{NaOH}$.

Final Answer: Hence, option (B) is correct. Hydrogen gas is evolved when Zinc granules are treated with Sodium hydroxide.