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Physical Chemistry

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8 Apr 2008 20:27:55 IST

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chemical reactions with high Ea values r genarlly

a) very fast

b)very slow

c) moderatily fast

d) spontaneous

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Comments (9)

niveditha mani

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8 Apr 2008 21:00:55 IST

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actually when Ea increases according to arrehenius eqn. the rate constant will increase so the rate of the reaction will also increase therefore the reaction will take place fastly thats it

varsha valli g.

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8 Apr 2008 21:10:15 IST

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yup chandini is right.
arrehenius eqn is K=Ae^-E/RT
=A*1/e^E/RT
so as E increases,the denominator becomeseven more smaller , the value on RHS bcomz larger and so K increases.
so rate inc with inc in energy gap.
!!!!!!!!!!!!!!!!!!!

harsh _27

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8 Apr 2008 22:00:25 IST

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The answer must be (b)very slow.

Because if Ea increases then no of molecules undergoing effective collisions decreases ( means molecules having sufficient energy to result in a product decreases).Therefore reaction slows down.

Even if you go with Arrhenius Equation K = Ae^-Ea/RT ,as the Ea increases K decreases hence reaction becomes very slow.

Varsha and Chandini plz recheck your answers.

prakhar

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8 Apr 2008 22:01:19 IST

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its a) vry fast..

Krishna Gopal Singh

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9 Apr 2008 11:18:30 IST

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Harsha is right. Ea increases means rate constant decreses. Well done harsha

chilbi

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9 Apr 2008 17:27:31 IST

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yup even i agree wid harsha coz activation energy is da amt of energy required by da reactants to complete da rxn & form products so da lesser da energy required more easily da formation will take place so gr8ter da rate of rxn

drishti sharma

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9 Apr 2008 19:16:04 IST

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YEAH HARSHA IS RIGHT.

ITS OPTN (b)

rohit

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9 Apr 2008 19:51:03 IST

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ya,
harsha is cent percent right

the rate of reaction decreases

varsha valli g.

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10 Apr 2008 14:12:56 IST

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sorry , i agree with harsha.dint see the - sign.
!!!!!!!!!!!!!!!!

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