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The first ionisation potential of Li is ...

The first ionisation potential of Li is `5.4` e V and the electron affinity of Cl is 3.6 eV . Calculate `Delta H` in kcal `mol^(-1)` for the reaction
`Li (g) + Cl (g) to Li^(+) + Cl^(-)`
Carried out at such low pressures that resulting ions do not combine with each other.

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Verified by Experts

The correct Answer is:
3
Overall reaction is divided into two partial equations as
`Li(g) to Li^(+) (g) +e^(-), triangleE_(1)=5.4eV`
`Cl(g)+e^(-) to Cl^(-) (g), triangleE_(2)=-3.5eV`
`triangleH=triangleE_(1)-triangleE_(2)=1.8eV=1.8 xx 23.06 =41.508" kcal mol"^(-1)`
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