Select the option containing the correct order of the given parameter.

When $Co(II)$ chloride is dissolved in concentrated $HCl$,a blue solution is obtained. Upon dilution with water,the colour changes to pink because:

$A$ brown ring is formed in the ring test for $NO_{3}^{-}$ ion. It is due to the formation of :-

$5.33 \text{ g}$ of $CrCl_3 \cdot 6H_2O$,which is a $1:3$ electrolyte,is dissolved in water and passed through a cation exchanger. The chloride ions in the eluted solution,on treatment with $AgNO_3$,result in $8.61 \text{ g}$ of $AgCl$. The ratio of moles of complex reacted and moles of $AgCl$ formed is . . . . . . $\times 10^{-2}$. (Nearest integer) [Molar mass in $\text{g mol}^{-1}$: $Cr = 52, Ag = 108, Cl = 35.5, H = 1, O = 16$]

Which among the following cations will form the lowest stability complex if the ligand remains the same?

Which of the following ions forms the most stable complex compound?