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When enthyne is passed through a red hot...

When enthyne is passed through a red hot tube, then formation of benzene takes place:
`Delta_(f)H_((C_(2)H_(2))(g))^(Theta) = 230 kJ mol^(-1)`
`Delta_(f)H_((C_(6)H_(6))(g))^(Theta) = 85kJ mol^(-1)`
Calculate the standard heat of trimerisation of ethyne to benzene:
`3C_(2)H_(2)(g) rarr C_(6)H_(6)(g)`

A

`205 kJ mol^(-1)`

B

`605 kJ mol^(-1)`

C

`-605 kJ mol^(-1)`

D

`-205 kJ mol^(-1)`

Text Solution

Verified by Experts

`[DeltaH_("reaction")^(Theta) = Delta_(f)H_((C_(6)H_(6)))^(Theta) - 3Delta_(f)H_((C_(2)H_(2)))^(Theta)`
`=85 - 3(230)`
`=- 605 kJ`
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