Question

Nitric acid is the most important oxi-acid formed by nitrogen. It is one of the major idustrial chemicals and is widely used. Nitric is manufactured by ostwald process in which catalytic oxidation of ammonia is done in following sequence as shown by reactions
`4 NH_(3) (g)+50_(2)(g) overset("Pt/Rh")underset("Catalyst")(rarr) 4 NO(g)+6 H_(2)O(g)` ...(i)
`2NO(g)+O_(2)(g) overset(1120 K)(rarr) 2NO_(2)(g)` ...(ii)
`3 NO_(2)(g)+H_(2)O(l) rarr 2 HNO_(3)(aq)+NO(g)` ...(iii)
In this process the aqueous nitric acid is obtained which can be concentrated by distillation to `~ 68.5%` by weight. Then concentration to 98% acid can be achieved by dehydration with concentrated sulfuric acid.
If 180 L of water completely reacts with `NO_(2)` produced to form nitric acid according to the above reactions, then the volume of air required at STP containing 20% of `NH_(3)` is
`(rho_(H_(2)O)=1 g//mL)`
A. `1.56xx10^(6) L`
B. `6.72 xx10^(4) L`
C. `3.36xx10^(6) L`
D. None of these

Answer 1

Correct Answer - C
Moles of water reacted `=(180xx10^(3))/18=10^(4)`
`:.` moles of `NO_(2)` required `=30xx10^(3)=` mole of `NH_(3)` required
`:.` volume of air at `STP=(30xx10^(3)xx22.4)/0.2=3.36xx10^(6) L`.