Write the equation for the lab. preparation of HNO₃ from potassium nitrate and conc. H₂SO₄

Potassium nitrate is prepared from KOH and nitric acid. State the type of reaction involved.

X, Y and Z are three crystalline solids which are soluble in water and have a common anion. To help you to identify X, Y and Z, you are provided with the following experimental observation. Copy and complete the corresponding inference.

A reddish-brown gas is obtained when X, Y and Z are separately warmed with concentrated sulphuric acid and copper turnings added to the mixture. The common anion is the ………….. ion.

Write a balanced equation for the reaction of conc. HNO₃ when added to copper turnings kept in a beaker.