question_answer 17)

\[\Delta {{U}^{{}^\circ }}\]of combustion of methane is \[-XkJmo{{l}^{-1}}\]. The value of\[\Delta {{H}^{{}^\circ }}\] is (i)\[=\Delta {{U}^{{}^\circ }}\] (ii) \[>\Delta {{U}^{{}^\circ }}\] (iii) \[

Answer:

\[C{{H}_{4}}(g)+2{{O}_{2}}(g)\to C{{O}_{2}}(g)+2{{H}_{2}}O(l)\] \[\Delta {{n}_{g}}=1-3=-2\] \[\Delta {{H}^{{}^\circ }}=\Delta {{U}^{{}^\circ }}-2RT\] \[\Delta {{H}^{{}^\circ }}=-X-2RT\] \[\Delta {{H}^{{}^\circ }}