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Using Arrhenius equation explain why the rate of a reaction increases with the decrease in activation energy? |
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Answer» Solution :(i) By Arrhenius equation, the rate CONSTANT k of a reaction at temperature T is represented as `k = P xx Z xx e^(-E_(a)//RT)` where A is a frequency factor, R is a gas constant and Ea is the activation ENERGY. (ii) As the temperature increases, the ratio `E_(a)//RT` DECREASES, but due to negative sign `(-E_(a)//RT)`, the value increases. (iii) As the activation energy `E_(a)` decreases, the energy barrier decreases, and more reactant molecules can cross the activation energy barrier. The collision frequency of successful COLLISIONS ALSO increases. (iv) As activation energy decreases the ratio`- E_(a)//RT` increases.Hence the rate constant and the rate of reaction increase with the decrease in activation energy. |
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