Question

One of the steps in the Ostwald process for the production of nitric acid involves oxidation of ammonia.

4NH3 (aq) + 5O2 (g) <---> 4NO (g) + 6H2O (g), Delta H= -905kJ

a) State the reaction conditions that favour the production of nitrogen monoxide.
b) A rhodium/platinum alloy is used as a catalyst. What effect does the catalyst have on the position of the equilibrium. Explain.
c) A relatively low pressure of about 710 kPa is used. Suggest why.
d) In the next step of the Ostwald process, nitrogen monoxide is mixed with air to form nitrogen dioxide:

2NO (g) + O2(g) <----> 2NO2(g) , Delta H= -115kJ

Why are the gases cooled for this reaction?



Thanks

Answer 1

a) State the reaction conditions that favour the production of nitrogen monoxide.
<b>If this question is asking for the best production AT EQUILIBRIUM then cool and low pressure. Under these conditions; however, the reaction is too slow to be useful and generally, in real practice, higher T and higher P are used.</b>

b) A rhodium/platinum alloy is used as a catalyst. What effect does the catalyst have on the position of the equilibrium. Explain.
<b>A catalyst changes ONLY the rate of the reaction. It has no effect on the final equilibrium.</b>

c) A relatively low pressure of about 710 kPa is used. Suggest why.
<b>Low pressure shifts the reaction to the side with fewer moles. That is the product side</b>

d) In the next step of the Ostwald process, nitrogen monoxide is mixed with air to form nitrogen dioxide:

2NO (g) + O2(g) <----> 2NO2(g) , Delta H= -115kJ

Why are the gases cooled for this reaction?
<b.Cooling uses up the heat produced and shifts the reaction to the right. </b>