CPC Inorganic Chemistry & Coordination Compounds 3

Question 1

According to Hard-Soft Acid-Base (HSAB) theory, hard acids preferentially bind to:

Accepted Answer

Hard bases that are small, electronegative, and weakly polarizable

Answer

Hard acids (small, high charge density) interact electrostatically and prefer hard bases (small, electronegative, low polarizability) based on charge–charge interactions.

Question 2

The chelate effect arises primarily from which thermodynamic contribution?

Accepted Answer

An increase in entropy as multiple monodentate ligands are released into solution

Answer

Replacing several monodentate ligands with one chelating ligand releases more free particles into solution, producing a significant entropy increase that drives complex stabilization.

Question 3

A coordination compound has its absorption maximum at 450 nm (violet-blue region). What color does this compound appear?

Accepted Answer

Orange-yellow

Answer

A compound that absorbs violet-blue light (~450 nm) transmits its complementary color, orange-yellow, which is what an observer sees.

Question 4

What is the correct IUPAC name for the complex ion [Fe(CN)6]4−?

Accepted Answer

Hexacyanoferrate(II)

Answer

Anionic complexes use the -ate suffix on the metal name; iron uses its Latin root (ferrate), and the Roman numeral indicates the +2 oxidation state, giving hexacyanoferrate(II).

Question 5

The measured magnetic moment of [MnCl4]2− is approximately 5.92 BM. How many unpaired electrons does this indicate?

Accepted Answer

5

Answer

Using the spin-only formula μ = √(n(n+2)) BM, a value of 5.92 BM solves to n = 5 unpaired electrons, consistent with high-spin Mn2+ (d5).

(CPC) Certified Professional Chemist Practice Test

(CPC) Certified Professional Chemist Practice Test

CPC Inorganic Chemistry & Coordination Compounds 3