Q. The heat of formations of $CO(g)$ and $CO_{2}(g)$ are $- 26.4$ kcal and $- 94.0$ kcal respectively. The heat of combustion of carbon monoxide will be
A) $- 67.6$ kcal
B) 36.5 kcal
C) $- 36.5\$kcal
D) $- 46.5$ kcal
Explanation
(a)
$C(s) + \frac{1}{2}O_{2}(g) \rightarrow CO_{2}(g);\mathrm{\Delta}H_{1} = - 26.4$
$C(s) + \frac{1}{2}O_{2}(g) \rightarrow CO_{2}(g);\mathrm{\Delta}H_{2} = - 96.0$
We have to find for $\mathrm{\Delta}H$, for reaction
$CO + \frac{1}{2}O_{2} \rightarrow CO_{2};\mathrm{\Delta}H_{1} = ?$
Eqs.$(ii) - (i)$, we get
$\mathrm{\Delta}H = - 94 - ( - 26.4) = - 67.6$ kcal
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.