Oxidising power of chlorine in aqueous solution can be determined by the parameters indicated below
`(1)/(2)CL_(2)(g)overset((1)/(2)Delta_(diss)H^(Theta))(rarr)Cl(g)overset(DeltaH_(Eg)^(Theta))(rarr)`
`Cl^(-)(g)overset(Delta_(hyd)H^(Theta))(rarr)Cl^(-)(aq)`
The energy involved in the conversion of `(1)/(2)Cl_(2)(g)` to
`Cl^(-)(aq)`
(Using the data `Delta_(diss)H_(Cl_(2))^(Theta)=240KJ mol^(-1)`)
`Delta_(Eg)H_(Cl)^(Theta)=-349KJmol^(-1)` ,
`Delta_(Eg)H_(Cl)^(Theta)=-381KJmol^(-1)`) will be

Options

A. ` + 142 kJ "mol"^(-1)`
B. ` -610 kJ "mol"^(-1)`
C. ` - 850 kJ "mol"^(-1)`
D. ` + 120kJ "mol"^(-1)`

Answer

B

Explanation

For the process , `1/2 Cl_2 (g) rarr Cl^-, DeltaH=?`
`Cl_2 (g) rarr 2Cl(g), Delta_(diss) H_(Cl_2)^( Theta) = 240 kJ "mol"^(-1)`.
`Cl_2 (g) rarr 2Cl(g), Delta_(eg) H_(Cl)^( Theta) = 349 kJ "mol"^(-1)`.
` Cl^(-) (g) +qs. rarrCl^(-) (sq), Delta_(hyd)H_(Cl^(-))^(theta)=- 381 kJ "mol"^(-1)`.
` DeltaH=(Delta_(diss)H_(Cl_2)^(theta))/2 + (Delta _(eg) H_(Cl)^(theta) + Delta_(hyd)H_(Cl^-)^(theta)`
` = (240)/2 + (-349) _ (-381) `
` =-610 hJ "mol"^(-1)`.