$(a)\, [Cu(NH_3)_4]^{2+} < [Cu(en)_2]^{2+} < [Cu(trien)]^{2+}$
Their formation entropy increases in the same order, because denticity of ligand increases
$(b)\, [Fe(H_2O)_6]^{3+} < [Fe(NO_2)_6]^{3-} < [Fe(NH_3)_6]^{3+}$
$NO_2^-$ is stronger ligand than $NH_3$
$(c)\, [Co(H_2O)_6]^{3+} < [Rh(H_2O)_6]^{3+} < [Ir(H_2O)_6]^{3+}$
$Z_{eff}$ value increases from $Co^{3+}$ to $Ir^{3+}$
$(d)\, [Cr(NH_3)_6]^{1+} < [Cr(NH_3)_6]^{2+} < [Cr(NH_3)_6]^{3+}$
Oxidation state of $Cr$ atom increases from $+ 1$ to $+3$.
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$(A)$ $\mathrm{Bi}_2 \mathrm{O}_5$ is more basic than $\mathrm{N}_2 \mathrm{O}_5$
$(B)$ $\mathrm{NF}_3$ is more covalent than $\mathrm{BiF}_3$
$(C)$ $\mathrm{PH}_3$ boils at lower temperature than $\mathrm{NH}_3$
$(D)$ The $\mathrm{N}-\mathrm{N}$ single bond is stronger than the $P-P$ single bond
(Molecular mass of $CHCl_3 = 119.5 \,u$ and molecular mass of $CH_2Cl_2 = 85\, u$)