Consider a reaction where S rxn = -315 J/K and H rxn = -45.6 kJ. Which statement
ID: 880116 • Letter: C
Question
Consider a reaction where S rxn = -315 J/K and H rxn = -45.6 kJ. Which statement is true about the spontaneity of this reaction?
Consider a reaction where S rxn = -315 J/K and H rxn = -45.6 kJ. Which statement is true about the spontaneity of this reaction?
This reaction is spontaneous at 25°C, but will become nonspontaneous if the temperature is decreased to -130°C. This reaction is nonspontaneous at 25°C but will become spontaneous if the temperature is increased to 145°C. Decreasing the temperature will have no effect on the spontaneity of the reaction. It is nonspontaneous at 25°C and will become even less spontaneous as the temperature decreases. This reaction is nonspontaneous at 25°C but will become spontaneous if the temperature is decreased to -130°C.Explanation / Answer
delta G = delta H - T delta S
when G= -ve , reaction will be spontaneous.
when G= +ve , reaction will be nonspontaneous.
Since both H and S = - ve, to be spontaneous TS has to be very small.
That is when T is very low then only reaction is spontaneous.
ans - This reaction is nonspontaneous at 25°C but will become spontaneous if the temperature is decreased to -130°C.