question_answer

For which one of the following equations \[\Delta H_{nreact}^{o}\] equal to \[\Delta H_{f}^{o}\] for the product?                                                                                                                                       [AIPMT 2003]

A)  \[Xe(g)+2{{F}_{2}}(g)\xrightarrow[{}]{{}}Xe{{F}_{4}}(g)\]       

B)  \[2CO(g)+{{O}_{2}}(g)\xrightarrow[{}]{{}}2C{{O}_{2}}(g)\]

C)       \[{{N}_{2}}(g)+{{O}_{3}}(g)\xrightarrow[{}]{{}}2C{{O}_{2}}(g)\]

D)                   \[C{{H}_{4}}(g)+2C{{l}_{2}}(g)\xrightarrow[{}]{{}}C{{H}_{2}}C{{l}_{2}}(\ell )+2HCl\,(g)\]

Correct Answer: A

Solution :

           

for the reaction

Because in this reaction one mole of  is formed from its constituent elements.