A chemist is preparing to analyse samples that will contain no more than 0.5 g of uranium. His procedure calls for preparing the uranium as U⁴⁺ ion and oxidizing it by MnO₄⁻ in acid solution: U⁴⁺ + Mn

Question

A chemist is preparing to analyse samples that will contain no more than 0.5 g of uranium. His procedure calls for preparing the uranium as U⁴⁺ ion and oxidizing it by MnO₄⁻ in acid solution: U⁴⁺ + MnO₄⁻ + H₂O $\to$ UO₂²⁺ + Mn²⁺ + H₃O⁺. If he wants to react the total U⁴⁺ sample with a maximum of 50 ml of KMnO₄ solution, what concentration does he choose? (U = 238)

Options:

Answer:

B

Solution:

U⁴⁺ $\to$ UO₂²⁺ loses 2e⁻; MnO₄⁻ gains 5e⁻, so 5 U⁴⁺ : 2 MnO₄⁻. mol U = 0.5/238 = 2.10 mmol, needing 2.10 x 2/5 = 0.840 mmol KMnO₄. Concentration = 0.840/50 = 0.0168 M, option (b).

TestHub · Accepted Answer

U⁴⁺ → UO₂²⁺ loses 2e⁻; MnO₄⁻ gains 5e⁻, so 5 U⁴⁺ : 2 MnO₄⁻. mol U = 0.5/238 = 2.10 mmol, needing 2.10 x 2/5 = 0.840 mmol KMnO₄. Concentration = 0.840/50 = 0.0168 M, option (b).

Chemistry - Redox Reactions Question with Solution | TestHub

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