A) Heat of formation of \[C{{O}_{2}}\]is (a + b)
B) Heat of combustion of\[C\]is (a + b)
C) \[\Delta {{H}_{3}}=\Delta {{H}_{1}}-\Delta {{H}_{2}}\]
D) All the above are correct statements
Correct Answer: D
Solution :
I: \[C(s)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow{{}}CO(g);\] \[\Delta {{H}_{1}}=a\] II: \[CO(g)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow{{}}C{{O}_{2}}(g);\] \[\Delta {{H}_{2}}=b\] III: \[C(s)+C{{O}_{2}}(g)\xrightarrow{{}}2CO(g);\] \[\Delta {{H}_{3}}=c\] On adding Eq. I and II, we get \[C(s)+{{O}_{2}}(g)\xrightarrow{{}}C{{O}_{2}}(g);\]\[\Delta H=\Delta {{H}_{1}}+\Delta {{H}_{2}}\]\[=a+b\] \[\therefore \] Heat of formation of \[C{{O}_{2}}=a+b\]and heat of combustion of\[C=a+b\] On subtracting Eq II from I, we get \[C(s)+C{{O}_{2}}(g)\xrightarrow{{}}2CO(g);\] \[\Delta {{H}_{3}}=\Delta {{H}_{1}}-\Delta {{H}_{2}}\]You need to login to perform this action.
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