Question

Which of the following elements produce ${\mathrm{H}}_2$ gas with sodium hydroxide?

• A. $\mathrm{Zn}$
• B. $\mathrm{Al}\mathrm{and}\mathrm{Pb}$
• C. $\mathrm{Si}\mathrm{and}\mathrm{Sn}$
• D. all of the above

Answer 1

The correct option is D

all of the above

Explanation for the correct option:

(d) all of the above

• $\mathrm{Zn},\mathrm{Al},\mathrm{Pb},\mathrm{Si},\mathrm{and}\mathrm{Sn}$ are the elements mentioned above.
• The following are the reactions of each with $\mathrm{NaOH}$:
• $\begin{array}{l}\mathrm{Zn}\left(\mathrm{s}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)\to {\mathrm{Na}}_2{\mathrm{ZnO}}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2\uparrow \left(\mathrm{g}\right)\\ 2\mathrm{Al}\left(\mathrm{s}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2{\mathrm{NaAlO}}_2\left(\mathrm{aq}\right)+3{\mathrm{H}}_2\uparrow \left(\mathrm{g}\right)\\ \mathrm{Pb}\left(\mathrm{s}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{Na}}_2{\mathrm{PbO}}_3\left(\mathrm{aq}\right)+2{\mathrm{H}}_2\uparrow \left(\mathrm{g}\right)\\ \mathrm{Sn}\left(\mathrm{s}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{Na}}_2{\mathrm{SnO}}_3\left(\mathrm{aq}\right)+2{\mathrm{H}}_2\uparrow \left(\mathrm{g}\right)\\ \mathrm{Si}\left(\mathrm{s}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{Na}}_2{\mathrm{SiO}}_3\left(\mathrm{aq}\right)+2{\mathrm{H}}_2\uparrow \left(\mathrm{g}\right)\end{array}$
• With sodium hydroxide, all of these elements form ${\mathrm{H}}_2$ gas.
• Hence this option is correct

Explanation for the incorrect options:

(a) $\mathrm{Zn}$

• With sodium hydroxide, all $\mathrm{Zn},\mathrm{Al},\mathrm{Pb},\mathrm{Si},\mathrm{and}\mathrm{Sn}$ form ${\mathrm{H}}_2$ gas
• So $\mathrm{Zn}$ is not only the one to react with sodium hydroxide, to form ${\mathrm{H}}_2$ gas
• Thus, this option is incorrect.

(b) $\mathrm{Al}\mathrm{and}\mathrm{Pb}$

• With sodium hydroxide, all $\mathrm{Zn},\mathrm{Al},\mathrm{Pb},\mathrm{Si},\mathrm{and}\mathrm{Sn}$ form ${\mathrm{H}}_2$ gas
• So $\mathrm{Al}\mathrm{and}\mathrm{Pb}$ is not only the one to react with sodium hydroxide, to form ${\mathrm{H}}_2$ gas
• Thus, this option is incorrect.

(c ) $\mathrm{Si}\mathrm{and}\mathrm{Sn}$

• With sodium hydroxide, all $\mathrm{Zn},\mathrm{Al},\mathrm{Pb},\mathrm{Si},\mathrm{and}\mathrm{Sn}$ form ${\mathrm{H}}_2$ gas
• So $\mathrm{Si}\mathrm{and}\mathrm{Sn}$ is not only the one to react with sodium hydroxide, to form ${\mathrm{H}}_2$ gas
• Thus, this option is incorrect.

Hence the correct option is (d) all of the above.