How does ammonia react with a solution of $Cu^{2+}$?

Which of the following is the correct order in the spectrochemical series of ligands?

Which of the following is not true for a ligand-metal complex?

The most stable complex among the following is

Which among the following is a correct decreasing order of thermodynamic stability of the complexes?

$CrCl_3 \cdot xNH_3$ can exist as a complex. $A$ $0.1 \ m$ aqueous solution of this complex shows a depression in freezing point of $0.558^{\circ} C$. Assuming $100 \%$ ionisation of this complex and that the coordination number of $Cr$ is $6$,the complex will be: (Given $K_f = 1.86 \ K \ kg \ mol^{-1}$)