Ammonia is a Lewis base. It forms complexes with cations. Which one of the following cations does not form a complex with ammonia?

Which of the following will $NOT$ give the characteristic test for $Fe^{2+}$ or $Fe^{3+}$ ions?

Identify the correct statements from the following:
$A$. $[Fe(C_2O_4)_3]^{3-}$ is the most stable complex among $[Fe(OH)_6]^{3-}$,$[Fe(C_2O_4)_3]^{3-}$ and $[Fe(SCN)_6]^{3-}$.
$B$. The stability of $[Cu(NH_3)_4]^{2+}$ is greater than that of $[Cu(en)_2]^{2+}$.
$C$. The hybridization of $Fe$ in $K_4[Fe(CN)_6]$ is $d^2sp^3$.
$D$. $[Fe(NO_2)_3Cl_3]^{3-}$ exhibits linkage isomerism.
$E$. $NO_2^-$ and $SCN^-$ ligands are $NOT$ ambidentate ligands.
Choose the correct answer from the options given below:

Choose the correct statements from the following:
$A$. Ethane$-1, 2-$diamine is a chelating ligand.
$B$. Metallic aluminium is produced by electrolysis of aluminium oxide in the presence of cryolite.
$C$. Cyanide ion is used as a ligand for the leaching of silver.
$D$. Phosphine acts as a ligand in Wilkinson's catalyst.
$E$. The stability constants of $Ca^{2+}$ and $Mg^{2+}$ are similar with $EDTA$ complexes.
Choose the correct answer from the options given below:

$[Cu(CN)_4]^{2-}$ is colourless as it absorbs light in

$AgCl$ is soluble in