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InterviewSolution
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If the bond dissociation energies of XY , `X_(2)` and `Y_(2)` ( all diatomic molecules )are in the ratio `1:1 : 0.5` and `DeltaH _(f) ` for the formation of XY of `- 200 kJ mol^(-1)` , the bond dissociation energy of `X_(2)` will beA. `100 kJ mol^(-1)`B. `200 kJ mol^(-1)`C. ` 400 kJ mol^(-1)`D. ` 800 kJmol^(-1)` |
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Answer» Correct Answer - D Suppose bond dissociation energy of XY `=akJ mol^(-1) , i.e., `BE ( XY )= a . Then BE `9X_(2)0= a, BE(Y_(2))= 0.5 a` Aim `: (1)/(2) X_(2)+ (1)/(2) Y_(2) rarr XY` `Delta_(r)H = BE` ( Reactants ) - BE ( Products ) `= [ (1)/(2) BE (X_(2)) + (1)/(2) BE(Y_(2)) ] = BE(XY)` `:. - 200 = ((a)/(2) + (0.5a)/( 2)) -a` or ` - 200 = - 0.25 a` or `a= 800 kJ mol^(-1)` |
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