What is the total number of donor atoms in $[Co(H_2O)(NH_3)_5]I_3$?

If $1/3$ of the total chlorine in the compound $CrCl_3 \cdot 6H_2O$ is precipitated by adding $AgNO_3$ to its aqueous solution,what is the possible structure of the compound?

The ligand in potassium ferricyanide is

Addition of excess of $AgNO_3$ to an aqueous solution of $1$ mole of $PdCl_2 \cdot 4 NH_3$ gives $2$ moles of $AgCl$. The conductivity of this solution corresponds to

The formula of alum is

Which of the following gives a white precipitate with $AgNO_3$?