Question

Pick the correct name of $\left.\left[ CoONH _{3}\right)_{3} Cl \right] C _{2}$

• A. chloropentammine cobalt (II) chloride
• B. pentammine chloro cobalt (III) chloride
• C. chloropentammine cobalt (III)
• D. pentammine cobalt (III) chloride

Answer 1

Answer: (B)

$\left[ Co \left( NH _{3}\right)_{5} Cl \right] Cl _{2}$
In this case the ligands are chloro and amine. The complex is cation and chloride is anion. The oxidation state of cobalt is III as
$x+5(0)-1-2 =0$
$x =+3$
Its name is pentammine chloro cobalt(III) chloride.