Question

Statement I: \( \mathrm{ClO_4^-} \), \( \mathrm{ICl_4^-} \), \( \mathrm{IBr_2^-} \) are tetrahedral, square planar and linear respectively.
Statement II: \( \left[\mathrm{Fe(CN)_6}\right]^{4-} \) is \( \mathrm{d^2sp^3} \) hybridized.

• A. Both Statement I and Statement II are correct
• B. Statement I is correct but Statement II is incorrect
• C. Statement I is incorrect but Statement II is correct
• D. Both Statement I and Statement II are incorrect

Hint:

In coordination chemistry, the geometry of a complex can be predicted based on the number of ligands and their arrangement around the central metal atom. The hybridization of the central atom is determined by the geometry of the complex.

Answer 1

The Correct Option is A

To determine the correctness of the statements given, let's analyze each statement separately:

Statement I: \( \mathrm{ClO_4^-} \), \( \mathrm{ICl_4^-} \), and \( \mathrm{IBr_2^-} \) are described as tetrahedral, square planar, and linear, respectively.

• \(\mathrm{ClO_4^-}\): Chlorate ion, \( \mathrm{ClO_4^-} \), has a central chlorine atom with four oxygen atoms arranged around it symmetrically. The molecule takes on a tetrahedral geometry due to this symmetrical arrangement.
• \(\mathrm{ICl_4^-}\): The iodine tetrachloride ion, \( \mathrm{ICl_4^-} \), has a central iodine atom surrounded by four chlorine atoms in a planar arrangement with two lone pairs, making its structure square planar.
• \(\mathrm{IBr_2^-}\): The iodine dibromide ion, \( \mathrm{IBr_2^-} \), has a linear geometry with the central iodine atom bonded to two bromine atoms, influenced by three lone pairs on iodine, causing a linear structure.

Thus, Statement I is accurate as it correctly describes the geometries.

Statement II: \( \left[\mathrm{Fe(CN)_6}\right]^{4-} \) is described as \( \mathrm{d^2sp^3} \) hybridized.

• In the complex \( \left[\mathrm{Fe(CN)_6}\right]^{4-} \), iron is in the +2 oxidation state, resulting in the electronic configuration of \( \mathrm{3d^6} \).
• The cyanide ions, being strong field ligands, cause pairing of the 3d electrons. This leads to the utilization of the 3d, 4s, and two 4p orbitals along with two 3d orbitals to form a \( \mathrm{d^2sp^3} \) hybridization.
• This results in an octahedral geometry for the complex.

Therefore, Statement II is correct as it describes the hybridization accurately.

Thus, Both Statement I and Statement II are correct.