NiCl₂ in the presence of dimethyl glyoxime (DMG) gives a complex which precipitates in the presence of NH₄OH, giving a bright red colour. Predict whether it is diamagnetic or paramagnetic.

• (A) paramagnetic
• (B) diamagnetic
• (C) both
• (D) none

The complex formed by NiCl₂ and dimethyl glyoxime (DMG) is known to exhibit specific magnetic properties based on its electron configuration. Nickel typically has an atomic number of 28, leading to an electron configuration of [Ar] 3d⁸ 4s². When it forms a complex with DMG, the nickel ion is usually in the +2 oxidation state, resulting in a 3d⁸ configuration.

Magnetic Properties

To determine whether the complex is diamagnetic or paramagnetic, we need to consider the presence of unpaired electrons:

• Paramagnetic: Substances with unpaired electrons, which are attracted to magnetic fields.
• Diamagnetic: Substances with all electrons paired, which are slightly repelled by magnetic fields.

Analysis of the Complex

In the case of the Ni(DMG)₂ complex, the nickel ion in the +2 state typically has two unpaired electrons in the 3d orbitals. This indicates that the complex will exhibit paramagnetic behavior.

Final Prediction

Based on this analysis, the correct answer is (A) paramagnetic.