The complex ion $[Co(en)_2Br_2]^+$ has two optical isomers. Their correct configurations are:

The reaction of aqueous $[Ni(H_2O)_6]^{2+}$ is performed by the addition of a bidentate ligand ethane-$1,2$-diamine $(en)$. Match the following:

$[Ni(H_2O)_6]^{2+} : en$ molar ratio	Colour of the product
$A. 1:1$	$I. \text{Pale blue}$
$B. 1:2$	$II. \text{Blue/Purple}$
$C. 1:3$	$III. \text{Violet}$

The correct match is:

$CuSO_{4(aq)} + 4NH_3 \rightarrow X,$ then $X$ is

$A$ 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:

Which of the following is a low spin complex?

$CuSO_{4(aq)}$ $\xrightarrow{H_2S \uparrow} M \downarrow$ $\xrightarrow[\text{Excess}]{KCN} N + O$
Then final products $N$ and $O$ are respectively.