Why bond dissociation energy of T2>D2>H2 ...??explain .

Why bond dissociation energy of T2>D2>H2 ...??explain .


3 Answers

Vikas TU
14149 Points
6 years ago
bond dissociation energy is the enrgy required to break the bonds b/w the moleculess and hence therfore,
T2 has highest mass containg more neutrons and enrgy required would be more.
Heavy isotopes genrally has more dissociation enrgy compare to than normal atoms.
Bhargavi V Jaiswal
15 Points
2 years ago
Tritium is a raioactive isotope of hydrogen which contains the maximum number of neutrons i.e. 2 among the other two isotopes which contain 0 and 1 neutron each. Now since tritium has max number of nucleons (2 neutrons and 1 proton) as compared to other two isotopes, the effective nuclear force or Z effective  increases and hence more energy is required to break the bond!
Niharika Singh
26 Points
one year ago
As we know that there are 3 isotopes of Hydrogen
1H1-----protium(H2).......1 proton and 1 electron
1H2------deuterium(D2).......1 proton,1 electron and 1 neutron.
1H3--------tritium(T2)........1 proton ,1electron and 2 neutron 
since T2 has more number of neutrons than other two(H2 and D2), that's why it's effective nuclear charge will be more, due to which it will hold its electrons more strongly and therefore to break bonds we need more bond dissociation enthalpy.
For D2 it has only 1 neutron ...there fore bond dissociation enthalpy will be less than T2 but will be more than H2.
H2 has no neutron so its bond dissociation  enthalpy will be least as compared to other isotopes  of hydrogen.
*bond dissociation  energy:- energy required to break bonds.

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