The spin-only magnetic moment value of M 3 + ion (in gaseous state) from the pairs Cr 3 + / Cr 2 + , Mn 3 + / Mn 2 , Fe 3 + / Fe 2 + and Co 3 + / Co 2 + that has negative standard electrode potential, is_____ B . M .

Step-by-step solution

Negative value of electrode potential for M 3 + M 2 + is for Cr + 3 Cr + 2 E Cr + 3 Cr + 2 0 = - 0 . 41 V Cr + 2 acts as a reducing agent readily Electronic configuration of Cr + 3   ion is Ar 4 s 0 3 d 3 Number of unpaired electrons, n = 3 Magnetic moment, μ = n n + 2 B . M       = 3 3 + 2 B . M = 15   B . M ≃ 4   B . M