Q. The bond dissociation energies of $X_2$, $Y_2$ and XY are in the ratio of 1 : 0.5 : 1. $\Delta H$ for the formation of XY is -200 kJ $mol^{-1}$. The bond dissociation energy of $X_2$ will be
A) 800 kJ $mol^{-1}$
B) 100 kJ $mol^{-1}$
C) 200 kJ $mol^{-1}$
D) 400 kJ $mol^{-1}$
Explanation
[Solution] $\frac{1}{2}a + \frac{1}{2}(0.5a) - a = -200$, so $-0.25a = -200$ and a = 800 kJ $mol^{-1}$. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.