All the oxides of nitrogen have positive values of dGof at 298K, but only one common oxide of nitrogen has a positive dSof. Identify that oxide of nitrogen without reference to thermodynamic data and explain.?

1 Answer
May 6, 2018

Well, let us write the formation reaction for the COMMON nitrogen oxides...

Explanation:

#N_2(g)+1/2O_2(g)rarr N_2O(g)#

#underbrace(1/2O_2(g) + 1/2N_2(g) rarr NO(g))_"entropically NEUTRAL process"#

#1/2N_2(g) + O_2(g) rarr NO_2(g)#

#N_2(g) + 5/2O_5(g) rarr N_2O_5(g)#

ONLY the formation of #NO(g)# is entropically neutral: one mole of gaseous particles results from one mole of gaseous reactants...the other nitrogen oxides FINISH with LESS gaseous particles than their reactant particles. Of course, you will have to check the Tables and see whether we gots the right end of the stick.