Q43 / 180 · COMEDK 2023 (Evening Shift) · Chemistry
Identify the correct IUPAC name of $[\mathrm{CoCl}_2(\mathrm{NO}_2)(\mathrm{NH}_3)_3]$
- Correct answerATriamminedichloridonitrito- $\mathrm{N}-\operatorname{cobalt}(\mathrm{III})$
- BTriamminedichloronitrito-O-cobaltate(III)
- CDichlorotriamminenitrito- $\mathrm{N}-\operatorname{cobalt}(\mathrm{II})$
- DDichloridotriamminenitrito-O-cobaltate(II)
Solution
The coordination compound is $[CoCl_{2}(NO_{2})(NH_{3})_{3}]$.
First, determine the oxidation state of the central metal atom, Cobalt (Co). Let the oxidation state be $x$. The ligands are $Cl^{-}$ (charge -1), $NO_{2}^{-}$ (charge -1), and $NH_{3}$ (neutral, charge 0). The complex is neutral, so the sum of charges is zero: $x + 2(-1) + 1(-1) + 3(0) = 0$, which gives $x - 3 = 0$, so $x = +3$.
Next, name the ligands in alphabetical order. The ligands are ammine ($NH_{3}$), chlorido ($Cl^{-}$), and nitrito-N ($NO_{2}^{-}$).
There are three ammine ligands, so use the prefix 'tri'. There are two chlorido ligands, so use the prefix 'di'. The ligand $NO_{2}$ is bonded through nitrogen, so it is named 'nitrito-N'.
Combining these, the alphabetical order is ammine, chlorido, nitrito-N. Thus, the name is triamminedichloridonitrito-N-cobalt(III).
Answer: Triamminedichloridonitrito- $\mathrm{N}-\operatorname{cobalt}(\mathrm{III})$
First, determine the oxidation state of the central metal atom, Cobalt (Co). Let the oxidation state be $x$. The ligands are $Cl^{-}$ (charge -1), $NO_{2}^{-}$ (charge -1), and $NH_{3}$ (neutral, charge 0). The complex is neutral, so the sum of charges is zero: $x + 2(-1) + 1(-1) + 3(0) = 0$, which gives $x - 3 = 0$, so $x = +3$.
Next, name the ligands in alphabetical order. The ligands are ammine ($NH_{3}$), chlorido ($Cl^{-}$), and nitrito-N ($NO_{2}^{-}$).
There are three ammine ligands, so use the prefix 'tri'. There are two chlorido ligands, so use the prefix 'di'. The ligand $NO_{2}$ is bonded through nitrogen, so it is named 'nitrito-N'.
Combining these, the alphabetical order is ammine, chlorido, nitrito-N. Thus, the name is triamminedichloridonitrito-N-cobalt(III).
Answer: Triamminedichloridonitrito- $\mathrm{N}-\operatorname{cobalt}(\mathrm{III})$
Hence, the correct answer is option: 'A'.