Q48 / 150 · MHT CET 2026 (17 April Shift 1) · Chemistry
What is EAN of Co in $[\text{Co}(\text{NH}_3)_6]^{3+}$?
- A$24$
- B$27$
- Correct answerC$36$
- D$30$
Solution
The effective atomic number (EAN) is calculated using the formula:
$\text{EAN} = Z - \text{O.S.} + 2 \times \text{C.N.}$
For the complex $[\text{Co}(\text{NH}_3)_6]^{3+}$, the central metal is cobalt.
Atomic number of Co ($Z$) = $27$
Oxidation state of Co ($\text{O.S.}$) = $+3$
Coordination number ($\text{C.N.}$) = $6$
Substituting the values into the formula:
$\text{EAN} = 27 - 3 + 2 \times 6$
$\text{EAN} = 24 + 12 = 36$
Answer: $36$
$\text{EAN} = Z - \text{O.S.} + 2 \times \text{C.N.}$
For the complex $[\text{Co}(\text{NH}_3)_6]^{3+}$, the central metal is cobalt.
Atomic number of Co ($Z$) = $27$
Oxidation state of Co ($\text{O.S.}$) = $+3$
Coordination number ($\text{C.N.}$) = $6$
Substituting the values into the formula:
$\text{EAN} = 27 - 3 + 2 \times 6$
$\text{EAN} = 24 + 12 = 36$
Answer: $36$
Hence, the correct answer is option: 'C'.