um this is what I got
a. NH4NO3 -------------> N2O + 2 H2O This is the correct equation ammonium nitrate does not produce oxygen when heated.
If you meant ammonium nitrite, not nitrate, in which case the equation is:
NH4NO2 ---------------> N2 + 2 H2O, but this doesn't produce oxygen either. If you teacher is ignorant of these facts, or gave you a bogus problem to solve, then use this equation (even though it doesn't exist): 2 NH4NO3 ----------------> 2 N2 + O2 + 4 H2O (Drax an "x' through the yields line to indicate that this reaction actually doesn't take place.
b. 2 NaHCO3 + H2SO4 --------------> Na2SO4 + 2 CO2 + 2 H2O
c. PCl5 + 4 H2O ---------> H3PO4 + 5 HCl
Hope this helped!