Please see the attached file.
(a) 4Fe (s) + 3O2 (g) --> 2Fe2O3 (s)
(b) O(g) + O (g) --> O2 (g)
(c) NH4Cl (s) --> NH3(g) + HCl (g)
(d) H2 (g) + Cl2 (g) --> 2HCl (g)
Entropy is actually a measurement of randomness. So gas > liquid > solid.
Also, entropy is greater if more ...
The solution explains how the entropy changes during the chemical reaction.