The coordination number of \(\mathrm{Ni}^{2+}\) is 4 .
\(\mathrm{NiCl}_{2}+\mathrm{KCN}\) (excess) \(\mathrm{A}\) (Cyano complex)
\(\mathrm{NiCl}_{2}+\) conc. \(\mathrm{HCl}\) (excess) \(\longrightarrow
\mathrm{B}\) (chloro complex)
The IUPAC name of \(\mathrm{A}\) and \(\mathrm{B}\) are:
(a) Potassium tetracyanonickelate (2), potassium tetrachloronickelate ( 2 )
(b) Tetracyanopotassiumnickelate (2), tetrachloropotassiumnickelate (2)
(c) Tetracyanonickel (2), tetrachloronickel ( 2 )
(d) Potassium tetracyanonickel (2), potassium tetrachloronickel (2)