The oxidising ability of chlorine in water can be assessed from the energy change for the following sequence:

1/2 Cl2(g) —ΔdissH°→ Cl(g) —ΔegH°→ Cl−(g)

1/2 Cl2(g) —ΔhydH°→ Cl−(aq)

Using the values ΔdissH°(Cl2) = 240 kJ mol−1, ΔegH°(Cl−) = −349 kJ mol−1, and ΔhydH°(Cl−) = −381 kJ mol−1,

Question

The oxidising ability of chlorine in water can be assessed from the energy change for the following sequence:

1/2 Cl2(g) —ΔdissH°→ Cl(g) —ΔegH°→ Cl−(g)

1/2 Cl2(g) —ΔhydH°→ Cl−(aq)

Using the values ΔdissH°(Cl2) = 240 kJ mol−1, ΔegH°(Cl−) = −349 kJ mol−1, and ΔhydH°(Cl−) = −381 kJ mol−1, the enthalpy change for converting 1/2 Cl2(g) into Cl−(aq) is:

Accepted Answer

−610 kJ mol−1. The enthalpy change for converting 1/2 Cl2(g) into Cl−(aq) is calculated by combining the dissociation energy of Cl2, the electron gain enthalpy of Cl, and the hydration enthalpy of Cl−. The values provided yield a net change of −610 kJ mol−1, indicating that the process is exothermic and demonstrates chlorine's strong oxidizing ability.

Solution

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