JEE MainChemistryd and f Block Elements
The standard electrode potential for the Ce ⁴⁺/ Ce ³⁺ couple is +1.74 V . Based on this value, which of the following statements correctly explains the behavior of Ce ⁴⁺ in aqueous solutions and its use in analytical chemistry?
Options
- AIt is thermodynamically incapable of oxidizing water, which makes its aqueous solutions highly stable for volu
- BIt oxidizes water rapidly, making it highly unstable and unsuitable as a reagent for volumetric titrations.
- CIt is thermodynamically capable of oxidizing water, but the reaction rate is very slow, allowing its solutions
- DIt acts as a strong reducing agent in water, converting water to hydrogen gas during titrations.
Correct answer
C. It is thermodynamically capable of oxidizing water, but the reaction rate is very slow, allowing its solutions
Step-by-step solution
The standard reduction potential of Ce ⁴⁺/ Ce ³⁺ is +1.74 V , which is significantly higher than the potential required to oxidize water (approximately 1.23 V ). Therefore, Ce ⁴⁺ is thermodynamically capable of oxidizing water to oxygen gas. However, this oxidation reaction is kinetically very slow. Because the reaction rate is negligible under ordinary conditions, aqueous solutions of Ce(IV) are kinetically stable. This combination of strong oxidizing power and kinetic stability in water makes Ce(IV) an excellent