Question

The oxidation number of Co in complex [Co(H$_2$NCH$_2$CHNH$_2$)$_3$]$_2$(SO$_4$)$_3$ is:

• A. 2
• B. 3
• C. 5
• D. 4

Answer 1

The Correct Option is B

To ascertain the oxidation state of cobalt (Co) within the complex [Co(H₂NCH₂CHNH₂)₃]₂(SO₄)₃, the subsequent steps are applied:

• The complex formula [Co(H₂NCH₂CHNH₂)₃]₂(SO₄)₃ comprises:
  • Cobalt [Co]
  • Tris(ethylenediamine) ligands [H₂NCH₂CHNH₂]
  • Sulfate ions (SO₄)
• Ethylenediamine (en) functions as a neutral ligand, thus it does not influence the complex's net charge.
• The sulfate ion (SO₄) carries a charge of -2. With three sulfate ions present, their cumulative charge contribution amounts to 3 × (-2) = -6.
• The complex, as a whole, is electrically neutral. Consequently, the combined charges within [Co(en)₃]₂ must equal +6 to counterbalance the -6 charge originating from the sulfate ions.
• Let 'x' represent the oxidation state of a single cobalt ion. The equation, considering two cobalt centers, is formulated as:
  \(x(2) + 0 = +6\)
• Solving for x yields:
  \(2x = 6\)
  \(x = 3\)
• Therefore, the oxidation number of Co in this complex is determined to be \(+3\).