Q. For the following two reactions, (i)$CH_{4}(g) + 2O_{2}(g) \rightarrow CO_{2}(g) + 2H_{2}O$ $\mathrm{\Delta}H = - 890.4\ kJ$ (ii)$2HgO(s) \rightarrow 2Hg(l) + O_{2}(g) - 181.6\ kJ$ Which one of the following statements is correct?
A) Both of them are exothermic
B) Both of them are endothermic
C) (i) is exothermic and (ii) is endothermic
D) (i) is endothermic and (ii) is exothermic
Explanation
(c)
For exothermic reaction, $\mathrm{\Delta}H = ( - )$ for endothermic reaction, $\mathrm{\Delta}H = ( + ).$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.