Which of the following ligands is neutral?

The denticity of the ligand present in the Fehling's reagent is $..........$.

Which of the following is a neutral complex?

Consider the coordination compound,$[Co(NH_3)_6]Cl_3$. In the formation of this complex,the species which acts as the Lewis acid is

Which of the following will give $Fe^{3+}$ ions in solution?

One mole of the complex compound $Co(NH_3)_5Cl_3$ gives $3$ moles of ions on dissolution in water. One mole of the same complex reacts with two moles of $AgNO_3$ solution to yield two moles of $AgCl_{(s)}$. The structure of the complex is