Write the balanced chemical equation with condition involved in the manufacture of nitric acid by Ostwal's process .

Explanation

MANUFACTURE .This method was established by withelm Ostwald.s (1902) .
In this method , `HNO_3` is manufactured by oxidation of ammonia . The main steps in this process are:
(i) Catalytic oxifation of ammonia . A gaseous mixture containing pure and dry ammonia and dust free dry air in the ratuo of 1:10 by volume , is passed through a steel shell or aluminium converted having platinum gauze heated electrically oxide and the reaction is exothermic .
`4NH_3+5O_2 underset (" 500K, 9bar") overset ("PtRh guage catalyst ") to 4NO+ 6H_2O`
To start with , the catalyst is heated electrically . As the reaction proceeds , enough heat is produced which maintain the required temperature and external
heating is stopped
(ii)Oxidation of nitruc oxide . The nitric oxide abtianed above is cooled and passed through a spacious chamber called oxidising chamber . The nitric oxide is oxidised to nitrogen dioxide .
`2NO (g) + O_2 (g) ` to `2NO_2(g)`
(iii) Absorption tower. The gases are then intorduced in the absorption tower whichis packed with acid proof stones . Water sprayed from the top dissolves nitrogen dioxide in the presence of oxygen to give about 60% nitric acid
`3NO_2 (g) + H_2O (1)` to `2HNO_3 (aq) + NO(g)`
`4NO _2 (g) + 2H_2O(1) + O_2(g) `to `4HNO_3 (aq) `
The acid flows down and is withdrow from the tower with the help of a tap . Further concent4raion of nitric acid can be done to 98% acid by dehydration with concentrated sulphuric acid .