Following are balanced equations describing heterogeneous reactions. Choose the appropriate equilibrium expression for each.
a.) 2Na2O2(s) + 2CO2(g) ---> 2Na2CO3(s) + O2(g)
b.) NH4HS(s) ---> H2S(g) + NH3(g)
c.) 2H2S(g) + O2(g) ---> 2S(s) + 2H2O(g)
d.) MnS(s) + H2O(l) ---> Mn2+(aq) + HS-(aq) + OH-(aq)