A) \[-1332.9\,kJ\,mo{{l}^{-1}}\]
B) \[-1322.9\,kJ\,mo{{l}^{-1}}\]
C) \[+1332.9kJ\,mo{{l}^{-1}}\]
D) \[+1322.9kJ\,mo{{l}^{-1}}\]
Correct Answer: B
Solution :
\[{{C}_{2}}{{H}_{4}}(g)+3{{O}_{2}}(g)\xrightarrow{{}}2C{{O}_{2}}(g)+2{{H}_{2}}O(g)\] Given, \[{{\Delta }_{f}}H_{(C{{O}_{2}})}^{o}=-393.5\,kJ\,\,mo{{l}^{-1}}\] \[{{\Delta }_{f}}H_{({{H}_{2}}O)}^{o}=-241.8\,kJ\,\,mo{{l}^{-1}}\] \[{{\Delta }_{f}}H_{({{C}_{2}}{{H}_{4}})}^{o}=+52.3\,kJ\,mo{{l}^{-1}}\] \[{{\Delta }_{r}}{{H}^{o}}\]= [sum of \[{{\Delta }_{f}}{{H}^{o}}\] values of products] -[sum of \[{{\Delta }_{f}}{{H}^{o}}\] values of reactants] \[=[2\times {{\Delta }_{f}}H_{(C{{O}_{2}})}^{o}+2\times {{\Delta }_{f}}H_{({{H}_{2}}O)}^{o}]\] \[-[\Delta {{ & }_{f}}H_{({{C}_{2}}{{H}_{4}})}^{o}+3\times \Delta {{ & }_{f}}H_{({{O}_{2}})}^{o}]\] \[=[2\times (-393.5)+2\times (-241.8)]-[(52.3)+0]\] (\[\because \] \[{{\Delta }_{f}}{{H}^{o}}\] for elementary substance \[=0\]) \[=[-787.0-486.6]-52.3\] \[=-1322.9kJ\,mo{{l}^{-1}}\]You need to login to perform this action.
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