Answer the following question briefly:
A metal does not react with dilute hydrochloric acid and dilute sulphuric acid in the absence of air. However, in the presence of air, it dissolves in dilute hydrochloric acid. When the same metal reacts with dilute nitric acid, a brown gas is not formed, but a colourless gas is liberated.
i. The metal is
ii. The gas liberated with dilute nitric acid is
ii. The gas liberated with dilute nitric acid is
iii. The balanced chemical equation for the reaction of metal with dilute nitric acid is