If the bond dissociation energies of $XY, X_{2}$ and $Y_{2}$ (all diatomic molecules) are in the ratio of $1 : 1 : 0.5$ and $Δ_{f} H$ for the formation of XY is $- 200 kJ {mol}^{- 1}$ . The bond dissociation energy of $X_{2}$ , will be

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!

An Intiative by Sri Chaitanya

$800 kJ {mol}^{- 1}$

$400 kJ {mol}^{- 1}$

$100 kJ {mol}^{- 1}$

$300 kJ {mol}^{- 1}$

answer is D.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

For the formation of XY, we have $\frac{1}{2} X_{2} (g) + \frac{1}{2} Y_{2} (g) ⟶ X Y (g)$

In terms of bond enthalpies, we have

$Δ_{f} H^{\circ} = \frac{1}{2} ε_{X_{2}} + \frac{1}{2} ε_{Y_{2}} - ε_{XY} = \frac{1}{2} ε_{X_{2}} + \frac{1}{2} (\frac{1}{2} ε_{X_{2}}) - ε_{X_{2}} = - \frac{1}{4} ε_{X_{2}}$

Hence $ε_{X_{2}} = - 4 (Δ_{f} H^{\circ}) = - 4 (- 200 kJ {mol}^{- 1}) = 800 kJ {mol}^{- 1}$

Watch 3-min video & get full concept clarity

tricks from toppers of Infinity Learn

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

🔥 Start Your JEE/NEET Prep at Just ₹1999 / month - Limited Offer! Check Now!

Get Expert Academic Guidance – Connect with a Counselor Today!