What metal is used with aqueous sodium hydroxide solution to test for nitrate ions in the solution?

A common nitrate test, known as the brown ring test can be performed by adding iron(II) sulfate to the solution, then slowly adding concentrated sulfuric acid

An alternative is to use Devarda's alloy, (Cu/Al/Zn), a reducing agent, which when mixed with nitrate and sodium hydroxide liberates ammonia. The ammonia produced, an alkaline gas, can be ?detected? with indicator paper. Aluminium with aqueous sodium hydroxide solution can also be used for this purpose.

Reaction:

3NO3-  +  8Al  +  5OH-  +  18H2O  ? 3 NH3  +  8 [Al(OH)4]-

Your answer is
a) aluminium

aluminium