Question

A metal whose alloy finds use in the construction of aircrafts in the powdered form is added to sodium hydroxide solution. A colourless gas was evolved and after reaction was over, the solution was colourless.
(a) Name the powdered metal added to sodium hydroxide solution.
(b) Name the gas evolved.
(c) Name the salt present in the colourless solution.

Answer 1

(a) Aluminium is the metal whose alloy finds use in the construction of aircraft. Aluminium is the powdered metal added to sodium hydroxide solution.

(b) When ​aluminium is added to the sodium hydroxide solution, it forms colourless solution of sodium aluminate with the evolution of hydrogen gas.

$$\begin{gathered} 2\mathrm{Al}\left(\mathrm{s}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2{\mathrm{NaAlO}}_2\left(\mathrm{s}\right)+3{\mathrm{H}}_2\left(\mathrm{g}\right) \\ \mathrm{Sodium}\mathrm{aluminate} \\ \left(\mathrm{colourless}\right) \end{gathered}$$

(c) The salt present in the colourless solution is sodium aluminate (NaAlO₂).