Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE MainChemistryRedox Reactions

When molecular iodine ( I ₂ ) reacts with hot and concentrated aqueous NaOH , it undergoes a disproportionation reaction. In the balanced chemical equation for this reaction (with the simplest whole number coefficients), what is the ratio of the stoichiometric coefficient of the oxidized product to that of the reduced product?

Options

  1. A5 : 1
  2. B1 : 1
  3. C1 : 5
  4. D1 : 2

Correct answer

C. 1 : 5

Step-by-step solution

Molecular iodine reacts with hot and concentrated NaOH to give sodium iodate ( NaIO ₃ ) and sodium iodide ( NaI ). This is a disproportionation reaction where iodine is both oxidized and reduced. The unbalanced ionic equation is: I ₂ + OH ^- IO ₃^- + I ^- + H ₂ O Oxidation half-reaction: I ₂ 2 IO ₃^- + 10 e ^- Reduction half-reaction: I ₂ + 2 e ^- 2 I ^- To balance the electrons, multiply the reduction half-reaction by 5: 5 I ₂ + 10 e ^- 10 I ^- Adding the two half-reactions gives: 6 I ₂ 2 IO ₃^- + 10 I ^- Simplify

Practice Redox Reactions on Quantrex Academy →

More from Redox Reactions

500 mL of 0.2 M MnO₄^- solution in basic medium when mixed with 500 mL of 1.5 M KI solution, oxidises iodide ions to liberate molecular iodine. This liberated iodine is then titrat 2026Given below are two statements: Statement I: Sodium dichromate and potassium dichromate are classified as primary standards in titrimetric analysis. Statement II: Phenolphthalein i 2026In order to oxidise a mixture of 1 mole each of FeC₂O₄ , Fe₂(C₂O₄)₃ , FeSO₄ and Fe₂(SO₄)₃ in acidic medium, the number of moles of KMnO₄ required is 2026500 mL of 1.2 M KI solution is mixed with 500 mL of 0.2 M KMnO ₄ solution in basic medium. The liberated iodine was titrated with standard 0.1 M Na ₂ ~S ₂ O ₃ solution in the prese 2026One mole of Cl ₂( ~g ) was passed into 2 L of cold 2 M KOH solution. After the reaction, the concentrations of Cl ⁻, ClO ⁻ and OH ⁻ are respectively (assume volume remains constant 2026X and Y are the number of electrons involved, respectively during the oxidation of I ⁻ to I ₂ and S ²⁻ to S by acidified K ₂ Cr ₂ O ₇ . The value of X + Y is _ _ _ _ . 2026200 cc of x 10⁻³ M potassium dichromate is required to oxidise 750 cc of 0.6 M Mohr's salt solution in acidic medium. Here x= _ _ _ _ . 2026Identify the correct statements : A. Hydrated salts can be used as primary standard. B. Primary standard should not undergo any reaction with air. C. Reactions of primary standard 2026 Full Redox Reactions list All JEE Main PYQs