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Thermodynamics

Question
CBSEENCH11006067

Which of the following is/are exothermic and which is/are endothermic/
left parenthesis straight i right parenthesis space Ca left parenthesis straight g right parenthesis space space space space rightwards arrow space space space space Ca to the power of 2 plus end exponent left parenthesis straight g right parenthesis space plus space 2 straight e to the power of minus
left parenthesis ii right parenthesis space straight O left parenthesis straight g right parenthesis space plus space straight e to the power of minus space space space rightwards arrow space space space straight O to the power of minus left parenthesis straight g right parenthesis
left parenthesis iii right parenthesis space straight N to the power of 2 minus end exponent left parenthesis straight g right parenthesis space plus space straight e to the power of minus space rightwards arrow space space straight N to the power of 3 minus end exponent left parenthesis straight g right parenthesis

Solution

(i) Endothermic (ionisation enthalpy is required).
(ii) Exothermic (first electron gain enthalpy is energy released).
(iii) Endothermic (higher electron gain enthalpies are energy required)