When ammonia is added to a cupric salt solution,the deep blue colour is observed; it is due to the formation of

Identify the lowest field strength ligand from the following.

If $1/3$ of the total chlorine in the compound is precipitated on adding $AgNO_3$ to its aqueous solution,which of the following is the correct structure of $CrCl_3 \cdot 6H_2O$?

Complex $A$ has a composition of $H_{12}O_{6}Cl_{3}Cr$. If the complex on treatment with conc. $H_{2}SO_{4}$ loses $13.5\%$ of its original mass,the correct molecular formula of $A$ is :
[Given : atomic mass of $Cr = 52 \ amu$ and $Cl = 35.5 \ amu$]

Among the following,the $\pi$-acid ligand is

In which one of the following pairs of ions is there an ion that forms a coordination compound with both aqueous sodium hydroxide and ammonia,and another ion that forms a coordination compound only with aqueous sodium hydroxide?