Exams › JEE Advanced › Chemistry

On adding acidified KMnO4 to a hot solution of oxalic acid, the purple colour fades slowly at first but then disappears rapidly. The reason is:

1. Mn2+ produced acts as an autocatalyst
2. CO2 is formed as a product
3. the reaction is exothermic
4. MnO4- catalyses the reaction

Correct answer: Mn2+ produced acts as an autocatalyst

Solution

The Mn2+ ions formed during the reduction of MnO4- act as an autocatalyst, so the rate increases once enough Mn2+ has accumulated, making decolourization rapid.

Related JEE Advanced Chemistry questions

• The count of d-electrons in Fe2+ differs from the number of:
• Which sequence of reactions accurately depicts the chemical processes involving iron and its associated compounds?
• When H2S interacts with an acidic solution of K2Cr2O7, which of the following compounds is not produced?
• When an excess amount of sodium thiosulfate is combined with copper sulfate in water, the resulting product is:
• Among the given lanthanoid ions, which one exhibits diamagnetic behavior? (Atomic numbers: Ce = 58, Sm = 62, Eu = 63, Yb = 70)
• Which of these statements is accurate?

⚔️ Practice JEE Advanced Chemistry free + battle 1v1 →