Question

An element $ X $ (atomic number 13) forms a complex of the type $[XCl(H_2O)_5]^{2+}$. What are the covalency and oxidation state of $ X $ in this complex?

• A. 5, +2
• B. 6, +2
• C. 5, +3
• D. 6, +3

Hint:

Covalency = number of coordinate bonds. Oxidation state = total charge balance using ligands and complex ion charge.

Answer 1

The Correct Option is D

The complex is: \[ [XCl(H_2O)_5]^{2+} \] There are: - 5 water ligands (neutral)
- 1 chloride ion (–1)
Let oxidation state of \( X \) be \( x \): \[ x + (-1) + 0 = +2 \Rightarrow x = +3 \] Covalency is number of sigma bonds formed by the central metal — here 6 (5 with \( H_2O \) and 1 with \( Cl^- \)).