MHT CET202527 Apr 2025Evening ShiftChemistryd and f Block ElementsActual
Which from following hydroxide acts as strongest base ?
Options
- ALa ( OH )₃
- BLu ( OH )₃
- CCe ( OH )₃
- DSm ( OH )₃
Correct answer
A. La ( OH )₃
Step-by-step solution
The basicity of lanthanide hydroxides decreases across the series from La(OH)₃ to Lu(OH)₃ . This trend results from lanthanide contraction , where the ionic radius of M³⁺ ions decreases across the lanthanide series. Smaller ionic radii lead to higher charge density and increased polarizing power of the cations. This strengthens the M-O bond while weakening the O-H bond in M(OH)₃ , making the hydroxide more acidic and less basic. The given lanthanide order is La Since La(OH)₃ corresponds to the first and largest cat