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The activation energy of an uncatalysed ...

The activation energy of an uncatalysed reaction is `E_(a)"kJ.mol"^(-1)` and that of the catalysed reaction is `(E_(a)-2)"kJ.mol"^(-1)` . If the change in enthalpy in absence of the catalyst is - xkJ , then what would be the change in enthalpy in presence of the catalyst ?

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Enthalpy does not change in presence of a catalyst . Thus the value of enthalpy will be same i.e., -xkJ.
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CHHAYA PUBLICATION-CHEMICAL KINETICS-WARM UP EXERCISE
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