What is the coordination number of $Co$ in $[CoCl_2(NH_3)_4]^+$?

Excess of silver nitrate solution is added to $100 \ mL$ of $0.01 \ M$ pentaaqua chloro chromium $(III)$ chloride solution. The mass of silver chloride obtained in grams is [Atomic mass of silver is $108$].

Which among the following is an ambidentate ligand?

The ligand $N[CH_2CH_2NH_2]_3$ is a:

The ion or molecule which forms a complex compound with a transition metal ion is called:

Which one is the most likely formula of $CrCl_3 \cdot 6H_2O$ if $\frac{2}{3}$ of the total chlorine in the compound is precipitated by adding $AgNO_3$ to its aqueous solution?