21H+21H→42He+10n
Mass of deuteron 21H=2.05amu
Mass of helium 42He=3.017amu
Mass of neutron 10n=1.009amu
Energy released = total binding energy of products – total binding energy of products
Q=((4×3.017+1×1.009)−2(2×2.05)
=13.077−8.2
=4.877amu
=4.877×931.5
=4542.9MeV