What is the value of the primary valence of $Co$ in $CoCl_{3}$?

In $K_4[Fe(CN)_6]$,the primary valency of iron is .........

Which of the following coordination compounds has a coordination number of $6$?

Identify the heteroleptic complex from the following.

In $K_4[Fe(CN)_6]$,which of the following statements is correct regarding the bonding?

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?