- ALa3+
- BU3+
- CYb3+
- DCf3+
Explanation:
Atomic and ionic radius of lanthanides decreases from La to Lu. Due to the contraction of lanthanide the decrease in ionic radius of the element in the lanthanide series from lanthanum to lutetium occurs.
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$M{g^{2 + }} + 2{e^ - } \to Mg(s);\,\,E = - 2.37\,V$
$C{u^{2 + }} + 2{e^ - } \to Cu(s);\,\,\,E = + 0.33\,V$
Statement - $I$: High concentration of strong nucleophilic reagent with secondary alkyl halides which do not have bulky substituents will follow $\mathrm{S}_{\mathrm{N}} 2$ mechanism.
Statement - $II$: A secondary alkyl halide when treated with a large excess of ethanol follows $\mathrm{S}_{\mathrm{N}} 1$ mechanism.
In the the light of the above statements, choose the most appropriate from the questions given below: