Among the statements $(a)-(d)$,the incorrect ones are:
$(a)$ Octahedral $Co(III)$ complexes with strong field ligands have very high magnetic moments.
$(b)$ When $\Delta_{0} < P$,the $d-$electron configuration of $Co(III)$ in an octahedral complex is $t_{2g}^{4} e_{g}^{2}$.
$(c)$ Wavelength of light absorbed by $[Co(en)_{3}]^{3+}$ is lower than that of $[CoF_{6}]^{3-}$.
$(d)$ If the $\Delta_{0}$ for an octahedral complex of $Co(III)$ is $18,000 \ cm^{-1}$,the $\Delta_{t}$ for its tetrahedral complex with the same ligand will be $16,000 \ cm^{-1}$.

$[Ni(CO)_4]$ is diamagnetic. Which of the following statements is correct for this complex?

The reaction of $K_3[Fe(CN)_6]$ with freshly prepared $FeSO_4$ solution produces a dark blue precipitate called Turnbull's blue. The reaction of $K_4[Fe(CN)_6]$ with $FeSO_4$ solution in the complete absence of air produces a white precipitate $X$,which turns blue in air. Mixing the $FeSO_4$ solution with $NaNO_3$,followed by a slow addition of concentrated $H_2SO_4$ through the side of the test tube,produces a brown ring.
Precipitate $X$ is:
$(A)$ $Fe_4[Fe(CN)_6]_3$
$(B)$ $Fe[Fe(CN)_6]$
$(C)$ $K_2Fe[Fe(CN)_6]$
$(D)$ $KFe[Fe(CN)_6]$
Among the following,the brown ring is due to the formation of:
$(A)$ $[Fe(NO)_2(SO_4)_2]^{2-}$
$(B)$ $[Fe(NO)_2(H_2O)_4]^{3+}$
$(C)$ $[Fe(NO)_4(SO_4)_2]$
$(D)$ $[Fe(H_2O)_5(NO)]SO_4$

The complexes given below show:

$A$ mixture $X$ containing $0.02 \ mol$ of $[Co(NH_3)_5SO_4]Br$ and $0.02 \ mol$ of $[Co(NH_3)_5Br]SO_4$ was prepared in $2 \ L$ of solution.
$1 \ L$ of mixture $X +$ excess $AgNO_3 \to Y$.
$1 \ L$ of mixture $X +$ excess $BaCl_2 \to Z$.
The number of moles of $Y$ and $Z$ are:

The volume (in $mL$) of $0.1 \ M$ $AgNO_3$ required for complete precipitation of chloride ions present in $30 \ mL$ of $0.01 \ M$ solution of $[Cr(H_2O)_5Cl]Cl_2$, as silver chloride is close to