Which ligand is used for the treatment of lead poisoning?

$K_4[Fe(CN)_6] + M^{x+}(aq.) \to M_4[Fe(CN)_6]_x \downarrow$
Which of the following cations does not respond to the above reaction?

What metal is present in Wilkinson's catalyst,which is used as a homogeneous catalyst for the hydrogenation of alkenes?

Which compound has electrovalent,covalent,coordinate as well as hydrogen bond?

In the complex ion $[Co(CN)_6]^{3-}$,the $Co^{3+}$ ion absorbs radiation of the violet color from the visible spectrum. What will be the color of its aqueous solution?

Hypo is used in photography because of its: