The standard enthalpy of solution of AgCl ( s ) in water is +65.5 kJ mol ⁻¹ . If the standard enthalpies of formation of AgCl ( s ) and Ag ^+( aq ) are -127.0 kJ mol ⁻¹ and +105.6 kJ mol ⁻¹ respectively, the standard enthalpy of formation of the Cl ^-( aq ) ion is :

Step-by-step solution

The dissolution reaction of AgCl ( s ) in water is: AgCl ( s ) Ag ^+( aq ) + Cl ^-( aq ) The standard enthalpy of solution is given by: _ sol H^ = _f H^ ( Ag ^+, aq ) + _f H^ ( Cl ^-, aq ) - _f H^ ( AgCl , s ) Substituting the given values: +65.5 = +105.6 + _f H^ ( Cl ^-, aq ) - (-127.0) 65.5 = 105.6 + _f H^ ( Cl ^-, aq ) + 127.0 65.5 = 232.6 + _f H^ ( Cl ^-, aq ) _f H^ ( Cl ^-, aq ) = 65.5 - 232.6 = -167.1 kJ mol ⁻¹ Answer: -167.1 kJ mol ⁻¹