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The bond energies of C=C and C-C at 298 ...

The bond energies of `C=C` and `C-C` at `298 K` are `590` and `331 kJ mol^(-1)`, respectively. The enthalpy of polymerisation per mole of ethaylene is

A

`-70 Kj`

B

`-72 Kj`

C

72 Kj

D

`-68` Kj

Text Solution

Verified by Experts

The correct Answer is:
B
The polymenzation of ethane may be represented as `nCH_(2)=CH_(2) to {-CH_(2) - CH_(2)-}n`.
One mole of C=C bond is decomposed and two moles of C-C bonds are formed per mole of ethylene.
`DeltaH = 590 -2 xx 331 = -72` KJ per mole.
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