Answer:
Reaction B is exothermic
Explanation:
From the context of thermodynamics, chemical reactions can be broadly classified as endothermic and exothermic reactions.
Endothermic reactions involve absorption of energy and show a positive value for the reaction enthalpy i.e. ΔH is positive. In contrast, exothermic reactions are accompanied by the release of energy and show a negative value for the enthalpy change i.e. ΔH is negative.
In a given chemical reaction energy is required to break bonds and it is released during the formation of new bonds.
The Reaction B is such that, the energy required to break bonds is less than energy released during formation bonds. Therefore, since there is a net release of energy, the reaction is exothermic.
