What is the equilibrium equation for FeS(s) + 2H3O+(aq) - Fe2+(aq) + H2S(aq) + 2H2O(l) ? Explain if possible !

Answer 1

This is the equilibrium equation. Are you looking for the Keq expression?
Keq = (Fe^2+)(H2S)(H2O)^2/H3O^+)^2
Some may not include the H2O in the constant; the general rule is it isn't included EXCEPT where it is involved in the reaction. Since it is produced in the reaction I included it.