At present, nitric acid is industrially prepared by the

Options

A. Haber process
B. Birkeland-Eyde process
C. Ostwald process
D. Contact process

Answer

3

Explanation

`HNO_(3)` is the most important oxoacid of nitrogen. (The three most important industrial acids in order of tonnages produced are (1) `H_(2)SO_(4)`, (2) `HNO_(3)` and (3) `HCl HNO_(3)` was originally made from`NaNO_(3)` or `KNO_(3)` and concentrated `H_(2)SO_(4)`. The first commercial method was the Bikeland-Eyed process. This sparked `N_(2)` and `O_(2)` together in an electric are furnace and passed the gas into water.
`N_(2)(g)+O_(2)(g) overset("spark")(hArr) NO (g) overset(O_(2))(rarr)NO_(2)(g) overset(H_(2)O)(rarr) HNO_(3)`
The process is now obsolete because of high cost of electricity. On a large scale it is prepared now mainly by Ostwald's process:
(i) The mixture of ammonia and air is passed over platinumrhodium gauze catalyst at `750=900^(@)`. The amount is oxidized to nitric oxide (NO):
`4NH_(3)+5O_(2)overset(Pt-Rh)underset(750-900^(@)C)(rarr)4NO+6H_(2)O+"Heat"`
The reaction is exothermic and the heat of reaction maintains the temperature of the catalyst.
The nitric oxide is then oxidized to nitrogen dioxide `(NO_(2))` by `O_(2)` form the air which is cooled to `50^(@)C` and absorbed in water to yield nitric acid:
`2NO+O_(2)rarr2NO_(2)`
`3NO_(2)+H_(2)Orarr2HNO_(3)+NO`
The resulting `NO` can be voltatilized and recycled.
we sometimes forget how our existence depends on thermodynamics. For example ,the first industrial synthesis of nitric acid was performed by simple conmbination of dinitrogen dioxygen ,and water ,using an electic are furnance to provide the energy to overcome the very high kinetic barrier.
Although industrially the kinetic factor was a problem, in reality it is a blessing , because without the energy barrier, all the dioxygen in the atmosphere would long ago have been converted to nitric acid and our seas would have become dilute nitric acid:
`.^(1)//_(2)N_(2)(g)+.^(1)//_(2)O_(2)(g)+.^(1)//_(2)H_(2)O(g)overset(Delta)(rarr)HNO_(3)(g)`