Assign $A, B, C, D$ from the given type of reaction.
$Fe(CN)_2 \downarrow + 4KCN \longrightarrow K_4[Fe(CN)_6]$

Which among the following is a correct decreasing order of thermodynamic stability of the complexes?

Which of the following correctly represents copper sulphate pentahydrate?

The stepwise formation of $[Cu(NH_{3})_{4}]^{2+}$ is given below:
$Cu^{2+} + NH_{3} \rightleftharpoons [Cu(NH_{3})]^{2+} \quad K_{1}$
$[Cu(NH_{3})]^{2+} + NH_{3} \rightleftharpoons [Cu(NH_{3})_{2}]^{2+} \quad K_{2}$
$[Cu(NH_{3})_{2}]^{2+} + NH_{3} \rightleftharpoons [Cu(NH_{3})_{3}]^{2+} \quad K_{3}$
$[Cu(NH_{3})_{3}]^{2+} + NH_{3} \rightleftharpoons [Cu(NH_{3})_{4}]^{2+} \quad K_{4}$
The values of stability constants $K_{1}, K_{2}, K_{3}$ and $K_{4}$ are $10^{4}, 1.58 \times 10^{3}, 5 \times 10^{2}$ and $10^{2}$ respectively. The overall equilibrium constant for dissociation of $[Cu(NH_{3})_{4}]^{2+}$ is $x \times 10^{-12}$. The value of $x$ is ...............
(Rounded off to the nearest integer)

Which of the following complex ions is the most stable?

White precipitate of $AgCl$ dissolves in aqueous ammonia solution due to formation of $.....$ .