QJEEM13Ch2316: JEE Main 2013 Chemistry - Class 11 JEEM13Ch2316 Solution: The first ionization potential of Na is 5.1 eV. The value of…

Ionization potential of Na means energy required to convert of Na to Na⁺ ion.

Na $$\to$$ Na⁺ + e^-          IE = 5.1 ev

Electron gain enthalpy of Na⁺ means energy required to convert Na⁺ ion to Na.

Na $$\to$$ Na⁺ + e^-          $$\mathrm{\Delta }{H}_{eq}$$ = - 5.1 ev

According to Lavoisier and Laplace law of thermochemistry, when we change the direction of reaction then the sign of energy also changes.