$0.001 \ mol$ of $Co(NH_3)_5(NO_3)(SO_4)$ was passed through a cation exchanger. The acid coming out of it required $20 \ mL$ of $0.1 \ M$ $NaOH$ for neutralization. Hence,the complex is:

Given below are two statements:
Statement $I$ : Dimethyl glyoxime forms a six-membered covalent chelate when treated with $NiCl_2$ solution in presence of $NH_4OH$.
Statement $II$ : Prussian blue precipitate contains iron both in $(+2)$ and $(+3)$ oxidation states.
In the light of the above statements,choose the most appropriate answer from the options given below:

The number of species having a square planar shape from the following is $........$.
$XeF_4$,$SF_4$,$SiF_4$,$BF_4^{-}$,$BrF_4^{-}$,$[Cu(NH_3)_4]^{2+}$,$[FeCl_4]^{2-}$,$[PtCl_4]^{2-}$

Identify the geometrical isomers of the following complexes:

The correct option$(s)$ regarding the complex $[Co(en)(NH_3)_3(H_2O)]^{3+}$ $(en = H_2NCH_2CH_2NH_2)$ is (are):
$A$. It has two geometrical isomers
$B$. It will have three geometrical isomers if bidentate 'en' is replaced by two cyanide ligands
$C$. It is paramagnetic
$D$. It absorbs light at longer wavelength as compared to $[Co(en)(NH_3)_4]^{3+}$

Sulphide ions react with sodium nitroprusside in a basic medium giving a coloured solution. In the reaction,the oxidation state of iron: