Given below are two statements : Statement (I) : Oxidising power of...

Statement I is true. The oxidising power of halogens decreases down the group in the order $F_2 > Cl_2 > Br_2 > I_2$. 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 ($Cl_2$) is added to an aqueous solution containing bromide ($Br^-$) or iodide ($I^-$) ions. Since $Cl_2$ is a stronger oxidising agent, it oxidises $Br^-$ to $Br_2$ and $I^-$ to $I_2$. The reaction is given by:
$Cl_2 + 2X^- \rightarrow 2Cl^- + X_2$ (where $X = Br, I$)
This is a non-metal displacement redox reaction. The liberated $Br_2$ or $I_2$ is then extracted into an organic solvent layer (like $CHCl_3$ or $CCl_4$), where it imparts a characteristic orange-red colour for $Br_2$ 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