Question

The IUPAC name for the complex $\left[Co\right(N{O}_2\left)\right(N{H}_3{)}_5]C{l}_2$ is

• A. Nitrito­-N­-pentaamminecobalt(III) chloride
• B. Nitrito-­N­-pentaamminecobalt(II) chloride
• C. Pentaammine nitrito-­N­-cobalt(II) chloride
• D. Pentaamminenitrito­-N­-cobalt(III) chloride.

Answer 1

The correct option is D Pentaamminenitrito­-N­-cobalt(III) chloride.

As per $IUPAC$ rules, for cationic complexes,
Ligands will be named first in alphabatical order then the central metal ion along with its oxidation state, then the anion part.
Let, the oxidation state of central metal ion be $x$
As we know $N{H}_3$ is neutral and $N{O}_2$ contains $-1$ charge and $Cl$ contains $-1$ charge
So,
$x-1+0-2=0$
$x-3=0$
$x=+3$
$\therefore$,
Pentaamminenitrito­-N­-cobalt(III) chloride.