InterviewSolution
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InterviewSolution
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A chemical reaction is spontaneous at 298 K but non-spontaneous at 350 K. Which one of the following is true for the reactionA. `{:(DeltaG,DeltaH,DeltaS),("_","_","+"):}`B. `{:(DeltaG,DeltaH,DeltaS),("+","+","+"):}`C. `{:(DeltaG,DeltaH,DeltaS),("-","+","-"):}`D. `{:(DeltaG,DeltaH,DeltaS),("-","-","-"):}` |
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Answer» Correct Answer - D `DeltaG=DeltaH-TDeltaS` For first condition, reaction will be spontaneous at all temperatures. For second option as `DeltaH=+ve` and `DeltaS` is +ve thus `DeltaG=underset(+ve)underbrace(DeltaH)-underset((-ve))underbrace(TDeltaS)` If temperature is high, `TDeltaS` will have higher negative value and reaction will be spontaneous Thus not true for given reaction. In case (c), `DeltaG`=ve, `DeltaS=+ve` implies spontaneous at all temperatures In case (e), `DeltaG=underset(-ve)underbrace(DeltaH)-underset(+ve)underbrace(TDeltaS)` At high temperature, second term will have high positive value and reaction will be non-spontaneous, thus case (e) is true for given example. |
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