Answer:
9.3/3=x/2,
Explanation:
9.3/3=x/2, where 9.3 is the new number of moles of O2, and 3 and 2 are the stoichiometric coefficients of O2 and H2S in the reaction. Solving for x yields that we need 6.2 moles of H2S to use all of the O2.