[shady145]

for the first one i say option (d)
reason:
write a chem eq
N2 + 3H2 <------> 2NH3
according to le chatliers principles then an increase in pressure will shift to the side with the least number of molecules, thus increasing the production of NH3
other reasons for this being the correct answer are
for option a.
the reaction is exothermic, and according to le chatlier the equilibirum will favour the reactants there fore producing less NH3
for option b
a catalyst only gets u to equilibium faster, it does not make the yeild of NH3 greater.
for option c.
there is no oxygen and carbon dioxide present in the reaction. if there were then an explosion would occur as u have H2 and O2 gas at a temperature of 500 degrees
therefore leaving d as the only choice