JEE Main 2026 — p Block Elements (Group 15, 16, 17 & 18) Question with Solution

Statement I is true. The oxidising power of halogens decreases down the group in the order $F_2>C{l}_2>B{r}_2>I_2$. A stronger oxidising halogen can displace a weaker oxidising halogen from its aqueous halide solution. This principle forms the basis of the layer test.

Statement II is true. In the layer test, chlorine water ($C{l}_2$) is added to an aqueous solution containing bromide ($B{r}^{-}$) or iodide ($I^{-}$) ions. Since $C{l}_2$ is a stronger oxidising agent, it oxidises $B{r}^{-}$ to $B{r}_2$ and $I^{-}$ to $I_2$. The reaction is given by:
$C{l}_2+2X^{-}\to 2C{l}^{-}+X_2$ (where $X=Br,I$)
This is a non-metal displacement redox reaction. The liberated $B{r}_2$ or $I_2$ is then extracted into an organic solvent layer (like $CHC{l}_3$ or $CC{l}_4$), where it imparts a characteristic orange-red colour for $B{r}_2$ or a violet colour for $I_2$, thereby identifying them.

Therefore, both Statement I and Statement II are true.

Answer: Both Statement I and Statement II are true