JEE Advanced 2015 · Paper 2 · Chemistry Q28

← JEE Advanced 2015 · Paper 2

ChemistryInteger+4Question 28 of 60

In dilute aqueous $\ce{H2SO4}$ , the complex diaquodioxalatoferrate(II) is oxidized by $\ce{MnO4-}$ . For this reaction, the ratio of the rate of change of $[\ce{H+}]$ to the rate of change of $[\ce{MnO4-}]$ is

Your answer

Answer and worked solution

Official answer: 8

Electrons lost per complex. In $\ce{[Fe(H2O)2(C2O4)2]^{2-}}$ :

Fe²⁺ → Fe³⁺: 1 e⁻;
two oxalates → 4CO₂: 4 e⁻.

That is 5 e⁻, matching one $\ce{MnO4-}$ (+7 → +2).

Balanced equation.
$\ce{[Fe(H2O)2(C2O4)2]^{2-} + MnO4- + 8H+ -> Fe^{3+} + Mn^{2+} + 4CO2 + 6H2O}.$

Ratio. 8 H⁺ are used per MnO₄⁻.

Answer: 8

Topics:Balancing redox reactions Rate of reaction and rate law

← Previous question Next question →

JEE Advanced 2015 · Paper 2, Chemistry question 28