The colour of $CoCl_3 \cdot 5NH_3 \cdot H_2O$ is

$Ag^{+} + NH_3 \rightleftharpoons [Ag(NH_3)]^{+}$; $k_1 = 3.5 \times 10^{-3}$
$[Ag(NH_3)]^{+} + NH_3 \rightleftharpoons [Ag(NH_3)_2]^{+}$; $k_2 = 1.7 \times 10^{-3}$
Then the formation constant of $[Ag(NH_3)_2]^{+}$ is

Write the correct order of the spectrochemical series for the given ligands.

$CuSO_4$ solution reacts with excess $KCN$ to give

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$NiCl_2 + NH_3$ (Excess) $\longrightarrow [Ni(NH_3)_6]^{2+}$

Assign $A, B, C, D$ from the given type of reaction.
$Cr(OH)_3 \downarrow + NH_3 \text{ (excess)} \longrightarrow [Cr(NH_3)_6]^{3+}$