A) 26.4 kcal
B) -26.4 kcal
C) 41.2 kcal
D) -41.2 kcal
Correct Answer: B
Solution :
According to Hesss law, the total heat changes occuring during a chemical reaction are independent of path. \[2\,CO(g)+{{O}_{2}}(g)\xrightarrow{{}}2C{{O}_{2}}(g),\,\,\Delta H=-135.2\,kcal\] \[C{{O}_{2}}(g)\xrightarrow{{}}CO+\frac{1}{2}{{O}_{2}}(g)\], \[\Delta H=\frac{135.2}{2}kcal\] ... (i) \[C+{{O}_{2}}(g)\xrightarrow{{}}C{{O}_{2}}(g)\], \[\Delta \,H=-94\,kcal\] ... (ii) Required equation \[C\,(s)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow{{}}CO(g),\,\Delta H=?\] Adding Eqs. ii) and (ii), we get \[C\,(s)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow{{}}CO(g),\,\,\Delta H=-26.4\,kcal\]You need to login to perform this action.
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