JEE Main20199 Jan 2019Evening ShiftChemistryClassification of Elements and Periodicity in PropertiesActual
When the first electron gain enthalpy ( Δ H e g ) of oxygen is - 141 k J / m o l , its second electron gain enthalpy is:
Options
- AA positive value
- BAlmost the same as that of the first
- CNegative, but less negative than the first
- DA more negative value than the first
Correct answer
A. A positive value
Step-by-step solution
Second electron gain enthalpy is always positive for every element because to overcome repulsion between an anion and electron, energy has to be supplied. O − + e − → O − 2   ;     Δ H e g = + v e