NEET-XII-Chemistry
Previous Year Paper year:2018
- #80The bond dissociation energies of ``X_2, Y_2 and XY``
are in the ratio of 1 : 0.5 : 1.
``\triangle``H for the formation
of XY is -200 kJ ``mol^{-1}``. The bond dissociation
energy of ``X_2`` will be
(1) 200 kJ ``mol^{-1}``
(2) 100 kJ ``mol^{-1}``
(3) 800 kJ ``mol^{-1}``
(4) 400 kJ ``mol^{-1}``digAnsr: 3Ans : (3)
Sol. let B.E. of x2 , y2 & xy are x kJ mol-1,
0.5x kJ mol-1 and x kJ mol-1 respectively
+ ▵ = 12 2
1 1
x y xy; H 200 kJmol
2 2
▵H = - 200 = (B.E)Reactant - (B.E)Product
= +
1 1
x 0.5x - 1 x
2 2
B.E of X2 = x = 800 kJ mol
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