Question

Name the gas evolved when potassium nitrate crystals are heated with concentrated sulphuric acid and pls give the equation also

Answer 1

⇒Sulphuric acid is non volatile acid.

⇒Thus, Sulphuric acid on reaction with Potassium Nitrate we get Fuming Nitric acid and Potassium Bisulphate.

                           <200°CKNO3 + H2SO4 ---------->KHSO4 +HNO3

Answer 2

Answer: The gas evolved is nitrogen dioxide $(NO_2)$

Explanation:

When potassium nitrate is heated in the presence of concentrated sulfuric acid, exchange of ions takes place.

The equation for the reaction of two is given by:

$KNO_3+H_2SO_4\rightarrow KHSO_4+HNO_3$

By Stoichiometry of the reaction:

1 mole of potassium nitrate reacts with sulfuric acid to produce potassium hydrogen sulfate and nitric acid.

This nitric acid produced is formed as a red fuming acid due to the formation of some nitrogen dioxide gas over it.