On adding excess of ammonium hydroxide to a copper chloride solution:

$5.33 \text{ g}$ 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 $\text{g mol}^{-1}$: $Cr = 52, Ag = 108, Cl = 35.5, H = 1, O = 16$]

An aqueous pink solution of Cobalt $(II)$ chloride changes to deep blue on addition of excess of $HCl$. This is because:

The stepwise stability constants of a complex are given below. What is its overall reaction stability constant $\beta_4$ ?
$M + L \rightleftharpoons ML ; K_1 = 1.0 \times 10^4$
$ML + L \rightleftharpoons ML_2 ; K_2 = 1.0 \times 10^3$
$ML_2 + L \rightleftharpoons ML_3 ; K_3 = 1.0 \times 10^3$
$ML_3 + L \rightleftharpoons ML_4 ; K_4 = 1.0 \times 10^2$
(Overall reaction : $M + 4L \rightleftharpoons ML_4$)

The purple color of $KMnO_4$ is due to which of the following?

Discuss the stability of coordination compounds.