Across lanthanide series the basicity of lanthanide hydroxides
Across lanthanide series the basicity of lanthanide hydroxides
Decreases
Increases
First decreases and then increases
First increases and then decreases
Solution
Across the lanthanide series the size of the cations decreases thereby decreasing ionic character and increasing covalent character of hydroxides of lanthanides. Thus, the basicity of hydroxides decreases.