Which of the following is an example of a homoleptic complex?

The number of neutral molecules or negative groups attached to the central metal atom in a complex ion is called:

Number of ambidentate ligands among the following is ................ $NO_2^{-}$,$SCN^{-}$,$C_2O_4^{2-}$,$NH_3$,$CN^{-}$,$SO_4^{2-}$,$H_2O$.

An example of a double salt is:

The coordination number of cobalt in the coordination compound $[Co(en)_2Br_2]Cl_2$ is ........ .

When $AgNO_3$ solution is added in excess to $1 \ M$ solution of $CoCl_3 \cdot X \ NH_3$,one mole of $AgCl$ is formed. What is the value of '$X$'?