Question

The Ostwald process for the commercial production of nitric acid from ammonia and oxygen involves the following steps:

Answer 1

Answer:

$12 NH_3 (g)+ 21 O_2 (g) + \longrightarrow 14 H_2O (l) + 8 HNO_3 (g) + 4 NO (g)$

Explanation:

The steps of the Ostwald process:

$4 NH_3 (g) + 5 O_2 (g) \longrightarrow 4 NO (g) + 6 H_2O (g)$

$2 NO (g) + O_2 (g) \longrightarrow 2 NO_2 (g)$

$3 NO_2 (g) + H_2O (l) \longrightarrow 2 HNO_3 (g) + NO (g)$

Combinning the equations:

$4 NH_3 (g) + 5 O_2 (g) \longrightarrow 4 NO (g) + 6 H_2O (g)$

+

$(2 NO (g) + O_2 (g) \longrightarrow 2 NO_2 (g))*2$

+

$(3 NO_2 (g) + H_2O (l) \longrightarrow 2 HNO_3 (g) + NO (g))*4/3$

=

$4 NH_3 (g)+ 4 NO (g)+ 7 O_2 (g) + 4 NO_2 (g) +4/3 H_2O (l) \longrightarrow 4 NO (g) + 6 H_2O (g) + 4 NO_2(g) + 8/3 HNO_3 (g) + 4/3 NO (g)$

Simplifying:

$4 NH_3 (g)+ 7 O_2 (g) + \longrightarrow 14/3 H_2O (l) + 8/3 HNO_3 (g) + 4/3 NO (g)$

$12 NH_3 (g)+ 21 O_2 (g) + \longrightarrow 14 H_2O (l) + 8 HNO_3 (g) + 4 NO (g)$

The overall reaction is endothermic becuase the formation of new chemical bonds requires energy consumption.