Explain why only all-glass apparatus should be used for the preparation of nitric acid by heating concentrated sulphuric acid and potassium nitrate.

In the laboratory preparation of HNO₃ - Name the reactants A [a liquid] and B [a solid] used.

Write the equation for the reaction in which copper is oxidized by concentrated nitric acid.

Identify the following substances: a dilute acid 'B' which does not normally give hydrogen when reacted with metals but does give a gas when it reacts with copper.