Identify the weak field ligand from the following.

Of the following complexes,the one with the largest value of crystal field splitting energy is

Arrange the following complex ions in increasing order of crystal field splitting energy $(\Delta_{0}):$ $[Cr(Cl)_{6}]^{3-}, [Cr(CN)_{6}]^{3-}, [Cr(NH_{3})_{6}]^{3+}$

The $CFSE$ for $[CoCl_6]^{4-}$ complex is $18000 \ cm^{-1}$. The $\Delta_t$ for $[CoCl_4]^{2-}$ will be ........... $cm^{-1}$.

The configurations of the complexes of manganese $A$ and $B$ respectively are $t_{2g}^3 e_g^1$ and $t_{2g}^4 e_g^0$. Then $A$ and $B$ are:

The complex ion that will lose its crystal field stabilization energy upon oxidation of its metal to $+3$ state is