The spin-only magnetic moments of [ Mn ( CN )₆ ]⁴⁻ and [ MnBr ₄ ]²⁻ in Bohr Magnetons, respectively, are

Step-by-step solution

array l [ Mn ⁺²( CN )₆ ]⁻⁴ Mn ⁺² 3 ~d ⁵ 4 ~s ⁰ 4 p array CN ⁻ is strong ligands so creates back paring effect of ( n -1) d orbitals configuration So, unpaired e ⁻=1 array l = n ( n +2) B , M =1.73 ~B . M array And in [ MnBr ₄ ]⁻² Br is a weak ligands so no back pairing effect on (n-1) d orbital so, unpaired e ⁻ is =5 = 5(5+2) = 35 =5.92 ~B . M