The configurations of the complexes of manganese A, B respectively are t_ 2 g ^3 e_g^1, t_ 2 g ^4 e_g^0 . Then A, B are

Step-by-step solution

The configuration t _ 2 ~g ^3 e _ g ^1 represents a total of 3+1= 4 electrons in the d-subshell with all electrons unpaired as there is a weak-field ligand. Thus, Mn is in +3 state and the complex 'A' will be [ Mn ( H ₂ O )₆ ]³⁺ . The configuration t_ 2 g ^4 e _ g ^0 represents the same oxidation state of Mn but with a strong-field ligand. Thus, the complex ' B ' will be [ Mn ( CN )₆ ]³⁻ .