Irregular trend in the standard reduction potential value of first row transition elements is due to

Options

A. Regular variation of first and second ionisation enthalpies
B. Irregular variation of sublimation enthalpies
C. Regular variation of sublimation enthalpies
D. Increase in no. of unpaired electrons

Answer

B

Explanation

There is no regular trend in the `E^@(M^(2+)//M)` values because of irregular variation of ionization energies and sublimation energies of the atoms of the members of the transition series.