Chemistry Q60 – JEE-MAIN 2026

Home Chemistry Periodicity & ElementsQuestion #499

Given below are two statements : Statement (I) : Oxidising power of halogens decreases in the order

F_{2} > C l_{2} > B r_{2} > I_{2}

, which is the basis of "Layer test". Statement (II) : "Layer test" to identify

B r_{2}

and

I_{2}

in aqueous solution involves the oxidation of bromide or iodide into

B r_{2}

I_{2}

respectively with

C l_{2}

, which is a type of displacement redox reaction. In the light of the above statements, choose the correct answer from the options given below :

Clue 1 of 3: Halogen Reactivity

Recall the trend in oxidising power of halogens down the group and its relation to their reactivity in displacement reactions.

🧠 Full Solution Path

Step 1: Evaluate Statement I✦ Active

Statement (I) claims that the oxidising power of halogens decreases in the order $F_{2} > C l_{2} > B r_{2} > I_{2}$ . This is a correct trend, as oxidising power generally decreases down a group for halogens due to decreasing electronegativity and electron affinity. This difference in oxidising power is indeed the basis for displacement reactions used in the 'Layer test' to identify halide ions. Thus, Statement I is true.

Step 2: Evaluate Statement II○ Expand

Statement (II) describes the 'Layer test'. The test involves the oxidation of bromide ( $B r^{-}$ ) or iodide ( $I^{-}$ ) ions into elemental $B r_{2}$ or $I_{2}$ respectively, typically using $C l_{2}$ water as the oxidising agent. For example:

2 B r^{-} (a q) + C l_{2} (a q) \to B r_{2} (a q) + 2 C l^{-} (a q)

2 I^{-} (a q) + C l_{2} (a q) \to I_{2} (a q) + 2 C l^{-} (a q)

These reactions are indeed displacement redox reactions, where a more reactive halogen ( $C l_{2}$ ) displaces a less reactive halide ion. The formed $B r_{2}$ or $I_{2}$ is then extracted into an organic solvent layer (e.g., $C C l_{4}$ or $C H C l_{3}$ ) to give characteristic colors, thereby identifying the original halide ions. The statement's phrasing 'to identify $B r_{2}$ and $I_{2}$ in aqueous solution involves the oxidation of bromide or iodide into $B r_{2}$ or $I_{2}$ ' refers to the process of forming and then identifying these products, which confirms the presence of the halide ions. Thus, Statement II is also true.

Step 3: Conclusion○ Expand

Since both Statement I and Statement II are true, the correct option is 'Both Statement I and Statement II are true'.

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Chemistry Question 60 – JEE-MAIN 2026

Clue 1 of 3: Halogen Reactivity

🧠 Full Solution Path