In the laboratory preparation of nitric acid from – KNO₃ or NaNO₃ state :

(i) the acid used

(ii) the type of apparatus used

(iii) the precautions to be taken during the preparation

(iv) the method of collection of the acid

(v) the method of identification of the product i.e., acid formed.

(i) Conc. Sulphuric Acid [H₂SO₄]

(ii) All glass apparatus is used

(iii) Precautions are:

1. Complete apparatus is made of glass since HNO₃ vapours are corrosive.
2. Conc. HCl is not used in place of conc. Sulphuric Acid (H₂SO₄) as a reactant, since being volatile itself it is not used to displace another volatile acid.
3. The reaction temperature is properly maintained and controlled to protect the glass apparatus, prevent further decomposition of the nitric acid and to avoid formation of hard residual crust of the corresponding sulphate.

(iv) Conc. HNO₃ vapours condense and are collected in water cooled receiver.

(v) The vapours obtained in the receiver on heating alone or with copper turnings evolve reddish brown fumes of nitrogen dioxide which turns acidified iron [II] sulphate solution brown proving that the vapours are of nitric acid.