Choose from the list of substances – Acetylene gas, aqua fortis, coke, brass, barium chloride, bronze, platinum. A catalyst used in the manufacture of nitric acid by Ostwald's process.

State your observation when —

Copper is heated with concentrated nitric acid in a hard glass test tube.

(i) State the special feature of the apparatus used in the laboratory preparation of nitric acid?

(ii) State why the temperature of the reaction mixture of HNO₃ is not allowed to rise above 200°C.

Give a balanced equation for – Ferric hydroxide reacts with nitric acid.