Question

Which one of the following is an exothermic reaction?

• A. $ {{N}_{2}}(g)+{{O}_{2}}(g)+180.8kJ\to 2NO(g) $
• B. $ C(\text{graphite})+2S(s)\to C{{S}_{2}}(l)-91.9kJ $
• C. $ {{N}_{2}}(g)+3{{H}_{2}}(g)-92kJ\to 2N{{H}_{3}}(g) $
• D. $ \text{C(g)+}{{\text{H}}_{\text{2}}}\text{O(g)}\to \text{CO(g)+}{{\text{H}}_{\text{2}}}\text{(g)-131}\text{.1kJ} $

Answer 1

Answer: (C)

The reactions in which products has lesser energy than reactants, the energy is released in the reaction and such reactions are known as exothermic reactions, e.g. $ {{N}_{2}}+3{{H}_{2}}\to 2N{{H}_{3}}+\text{92 kJ} $ In this equation energy is released. So, it is an example of exothermic reaction.