# Can a reaction be both exothermic and non spontaneous? [closed]

Can a reaction be both exothermic and nonspontaneous?

The spontaneity of a reaction is given by $$\Delta G$$

$$\Delta G < 0$$ = spontaneous reaction

$$\Delta G > 0$$ = nonspontaneous reaction

$$\Delta G$$ is quantitatively described by the formula

$$\Delta G = \Delta H - T \Delta S$$

$$\Delta H$$ is negative (exotermic reaction)

When $$T \Delta S$$ product is more negative (smaller) than $$\Delta H$$, we have $$\Delta G > 0$$ and the reaction is nonspontaneous

• Is there an example of such a reaction though? – Safdar Faisal Jul 25 '20 at 14:16
• No, i agree with what you say. However it would be better if you could add an example of such a situation. Also, this would be temperature dependant. You might want to add that/ – Safdar Faisal Jul 25 '20 at 14:20
• exothermic non spontaneous not endo thermic – Safdar Faisal Jul 25 '20 at 14:25
• You can add that to the answer (+1) – Safdar Faisal Jul 25 '20 at 14:36
• You can think of any combustion reaction – Namburu Karthik Jul 25 '20 at 16:39