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The standard enthalpies of formation of ...

The standard enthalpies of formation of `SF_(6)(g)` , `S(g)` and `F(g)` are `-1150` , `+280` and `+85KJmol^(-1)` . Thus, average bond energy of `(S-F)` in `SF_(6)` is

A

`309.16KJmol^(-1)`

B

`1855KJmol^(-1)`

C

`11.130xx10^(3)KJmol^(-1)`

D

`323.33KJmol^(-1)`

Text Solution

Verified by Experts

The correct Answer is:
D
`S(g)+6F(g)rarrSF_(6)(g)`
Based on `BE` values
`Delta_(f)H^(@)(SF_(6))=-1100=Delta_(f)H^(@)(S,g)`
`+6Delta_(f)H^(@)(F,g)-6(BE)_(S-F)`
`-1150=280+6xx85-6(BE)_(S-F)`
`:. (BE)_(S-F)=(280+510+1150)/(6)=323.33KJmol^(-1)`
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