Question

The separation of lanthanoids by ion exchange method is based on

• A. basicity of the hydroxides
• B. size of the ions
• C. the solubility of their nitrates
• D. the oxidation state of the metal ion

Answer 1

The correct option is B size of the ions

Explanation :

Separation of lanthanoids by ion-exchange method is based on the fact that radii of hydrated lanthanoid ions increase with increasing atomic number. Thus, when a solution of many lanthanoid ions passes slowly through the column of cation exchange resin, the heavier ions will come through first.