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)` isA. `309.16KJmol^(-1)`B. `1855KJmol^(-1)`C. `11.130xx10^(3)KJmol^(-1)`D. `323.33KJmol^(-1)`

The standard enthalpies of formation of `SF_(6)(g)` , `S(g)` and `F(g)

1.	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)` isA. `309.16KJmol^(-1)`B. `1855KJmol^(-1)`C. `11.130xx10^(3)KJmol^(-1)`D. `323.33KJmol^(-1)`
Answer» Correct Answer - B `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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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)` isA. `309.16KJmol^(-1)`B. `1855KJmol^(-1)`C. `11.130xx10^(3)KJmol^(-1)`D. `323.33KJmol^(-1)`

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