Among the following metal carbonyl, the C-O bond order is lowest in

Match the complexes in Column I with their properties listed in Column II. Indicate your answer by darkening the appropriate bubbles of the 4 $$\times$$ 4 matrix given in the ORS.

The coordination of $$\mathrm{Ni^2+}$$ is 4.

$$\mathrm{NiCl_2+KCN}$$ (excess) $$\to$$ A (cyano complex)

$$\mathrm{NiCl_2+ conc.~HCl}$$ (excess) $$\to$$ B (chloro complex)

The IUPAC names of $$\mathbf{A}$$ and $$\mathbf{B}$$ are

The coordination of $$\mathrm{Ni^2+}$$ is 4.

$$\mathrm{NiCl_2+KCN}$$ (excess) $$\to$$ A (cyano complex)

$$\mathrm{NiCl_2+ conc.~HCl}$$ (excess) $$\to$$ B (chloro complex)

Predict the magnetic nature of $\mathbf{A}$ and $\mathbf{B}$.