CBSE Class 12 · 2003 · All India · Chemical KineticsShort Answer

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What is known as 'activation energy'? How is the activation energy affected by (i) the use of a catalyst and (ii) a rise in temperature?

Solution

Activation energy is the minimum extra energy, above their average energy, that reactant molecules must acquire to form the activated complex and change into products.
(i) A catalyst lowers the activation energy by providing an alternative reaction path.
(ii) A rise in temperature does not change

E_{a}

; it increases the fraction of molecules having energy

\geq E_{a}

, which is why the rate increases.

CBSE Class 12 Board · 2003 · All India · Subjective

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