State why nitric acid is a strong oxidizing agent and yields varying products such as NO, NO₂ on reaction with metals, non-metals etc.

Give an equation for reaction of conc. HNO₃ with :

(i) carbon

(ii) copper.

State how you would obtain:

(i) hydrogen

(ii) nitric oxide

(iii) nascent chlorine – from nitric acid.

State the concentration of nitric acid used in each case.

State why hydrogen is liberated when zinc reacts with dil. HCl but not with dil. HNO₃.