Over a wide temperature range the reaction M2O3 s Cs Ms C

Over a wide temperature range, the reaction, M2O3 (s) + C(s) ? M(s) + CO2 (g), is spontaneous at low temperatures but non-spontaneous at high temperatures. If we assume that, since the physical states do not change, the values of ?Ho and ?So are constant over this temperature range, we can then deduce that

A. ?H < 0 and ?S > 0

B. ?H < 0 and ?S < 0

C. ?H > 0 and ?S < 0

D. ?H > 0 and ?S > 0

E. all the above

F. none of the above

Solution

G=H-TS

so the correct option is H<0 and S<0

so B