Which characteristic of ammonia makes it more effective in displacing water ligands in copper complexes?

Which characteristic of ammonia makes it more effective in displacing water ligands in copper complexes?

• A. It has a higher boiling point than water
• B. It is a neutral molecule
• C. It has more lone pairs than water
• D. It has more hydrogen bonds than water

Answer: (C)

The characteristic of ammonia that makes it more effective in displacing water ligands in copper complexes is its greater number of lone pairs compared to water. Ammonia (NH3) has one nitrogen atom that carries a lone pair of electrons, while each water (H2O) molecule has two lone pairs on its oxygen atom. In coordination chemistry, ligands with available lone pairs can form coordinate covalent bonds with metal centers, such as the copper ion in this case. The nitrogen atom in ammonia can readily donate its lone pair to a copper ion to form a stronger bond than that of water, which contains two lone pairs but is typically involved in hydrogen bonding rather than acting as a strong ligand. Moreover, while ammonia is indeed a neutral molecule, which also plays a role in its ability to displace water ligands, the presence of multiple lone pairs—rather than just being neutral—enables ammonia to interact more effectively with transitional metal ions like copper. The boiling point of ammonia being higher than water or its capacity for hydrogen bonds does not directly correlate with its ligand-displacement capabilities. Thus, the ability to coordinate more effectively is primarily due to the number and availability of lone pairs on the ammonia molecule.

The characteristic of ammonia that makes it more effective in displacing water ligands in copper complexes is its greater number of lone pairs compared to water. Ammonia (NH3) has one nitrogen atom that carries a lone pair of electrons, while each water (H2O) molecule has two lone pairs on its oxygen atom.

In coordination chemistry, ligands with available lone pairs can form coordinate covalent bonds with metal centers, such as the copper ion in this case. The nitrogen atom in ammonia can readily donate its lone pair to a copper ion to form a stronger bond than that of water, which contains two lone pairs but is typically involved in hydrogen bonding rather than acting as a strong ligand.

Moreover, while ammonia is indeed a neutral molecule, which also plays a role in its ability to displace water ligands, the presence of multiple lone pairs—rather than just being neutral—enables ammonia to interact more effectively with transitional metal ions like copper. The boiling point of ammonia being higher than water or its capacity for hydrogen bonds does not directly correlate with its ligand-displacement capabilities. Thus, the ability to coordinate more effectively is primarily due to the number and availability of lone pairs on the ammonia molecule.