The basic nature of the Lanthanide hydroxides decreases from `Ce(OH)_(3)`, to `Lu(OH)_(3)`This is due to

Options

A. Decrease in ionic radius
B. Due to lanthanoid contraction
C. Increase in metallic character
D. All of these

Answer

To understand why the basic nature of lanthanide hydroxides decreases from Ce(OH)₃ to Lu(OH)₃, we can break down the explanation into several steps:

### Step 1: Understanding Basic Nature
Basic nature refers to the ability of a compound to donate hydroxide ions (OH⁻) in solution. In the case of lanthanide hydroxides, the basicity is influenced by the ionic character of the metal-hydroxide bond.

**Hint:** Recall that basicity is related to the ability of a compound to release hydroxide ions in solution.

### Step 2: Analyzing Ionic Charge
Both Ce(OH)₃ and Lu(OH)₃ have the same charge on their metal ions (+3). However, as we move from Ce to Lu in the lanthanide series, the size of the metal ion decreases due to the lanthanide contraction.

**Hint:** Consider how the charge on the metal ion affects its interaction with hydroxide ions.

### Step 3: Lanthanide Contraction
The lanthanide contraction refers to the gradual decrease in ionic radii of the lanthanide elements as we move from Ce to Lu. This contraction occurs due to the ineffective shielding of the nuclear charge by the f-electrons, leading to a stronger attraction between the nucleus and the electrons.

**Hint:** Think about how the size of the metal ion influences its ability to interact with hydroxide ions.

### Step 4: Decrease in Ionic Character
As the ionic radius decreases, the covalent character of the metal-hydroxide bond increases. A more covalent bond means that the metal ion holds onto the hydroxide ions more tightly, making it less likely to release them into solution.

**Hint:** Reflect on how the nature of the bond (ionic vs. covalent) affects the release of hydroxide ions.

### Step 5: Conclusion on Basic Nature
Since the basicity of the hydroxides is related to the ability to release hydroxide ions, the decrease in ionic character (and increase in covalent character) as we move from Ce(OH)₃ to Lu(OH)₃ leads to a decrease in basicity.

**Hint:** Summarize how the changes in ionic radius and bond character affect the overall basicity of the hydroxides.

### Final Answer
The basic nature of lanthanide hydroxides decreases from Ce(OH)₃ to Lu(OH)₃ due to the decrease in ionic radius leading to an increase in covalent character of the metal-hydroxide bond, which in turn reduces the ability to release hydroxide ions.