Search any question & find its solution
Question:
Answered & Verified by Expert
Paragraph:
The coordination number of $\mathrm{Ni}^{2+}$ is 4 .
$\mathrm{NiCl}_2+\mathrm{KCN}$ (excess) $\rightarrow A$ (cyano complex)
$\mathrm{NiCl}_2+$ conc. $\mathrm{HCl}$ (excess) $\rightarrow B$ (chloro complex)Question:
Predict the magnetic nature of $A$ and $B$ are
Options:
The coordination number of $\mathrm{Ni}^{2+}$ is 4 .
$\mathrm{NiCl}_2+\mathrm{KCN}$ (excess) $\rightarrow A$ (cyano complex)
$\mathrm{NiCl}_2+$ conc. $\mathrm{HCl}$ (excess) $\rightarrow B$ (chloro complex)Question:
Predict the magnetic nature of $A$ and $B$ are
Solution:
2367 Upvotes
Verified Answer
The correct answer is:
$A$ is diamagnetic and $B$ is paramagnetic with two unpaired electrons
$A$ is diamagnetic and $B$ is paramagnetic with two unpaired electrons
In it unpaired orbital is not present, so it is diamagnetic in character (square planar shape) In chloro complex $\mathrm{K}_2\left[\mathrm{Ni}(\mathrm{Cl})_4\right]$, complex ion is $\left[\mathrm{Ni}^2\left(\mathrm{Cl}_4\right)\right]^{2-}$ and $\mathrm{Ni}$ is present $\mathrm{Ni}^{2+}$ or $\mathrm{Ni}(\mathrm{II})$, so
$$
\mathrm{Ni}^2+=1 s^2, 2 s^2 2 p^6, 3 s^2 3 p^6 3 d^8, 4 s^0
$$
In $\left.\left[\mathrm{Ni}_{\left(\mathrm{Cl}_4\right)}\right)\right]^2$ ion, $\mathrm{Ni}^{2+}$ is present as follows due to weaker ligand character is $\mathrm{Cl}^{-}$ion. $\left(\mathrm{Cl}^{-}\right.$is weak field ligand). So, it is unable to pair up the electron and $\mathrm{Ni}^{2+}$ needs four empty orbitals to accommodate four $\mathrm{Cl}^{-}$ligand. Thus, $\left(\mathrm{NiCl}_4\right)^{2-}$ shows $s p^3$-hybridisation (Tetrahedral shapes)
Hence, due to presence of unpaired orbitals, it is paramagnetic in character.
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.