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For following reactions A overset( 400...

For following reactions
`A overset( 400K)( rarr) ` Product
`A underset("catalyst")overset("200K")(rarr)` Product
it was found that the `E_(a)` is decreased by 20 kJ` //` mol in the presence of catalyst. If the rate remains unchanged, the activation energy for catalysed reaction is ( Assume per exponential factor is same ) `:`

A

`40kj//mol`

B

`20kj//mol`

C

`80kj//mol`

D

`35kj//mol`

Text Solution

Verified by Experts

The correct Answer is:
B
`k_("uncatalysed")=k_("catalysed")`
`Ae^(-Ea_(1)//RT_(1)=Ae^(-Ea_(2)//RT_(2)" "implies(Ea_(1))/(T_(1))=(Ea_(2))/(T_(2))impliesEa_(1)=Ea_(2)+20`
`implies(Ea_(2)+20)/400=(Ea_(2))/20implies2Ea_(2)=Ea_(2)+20impliesEa_(2)=20`
Activation energy of the catalysed reaction = 20 kJ/mol
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