Given below are two statements : Statement (I) : Oxidising power of halogens decreases in the order F_2 > Cl_2 > Br_2 > I_2, which is the basis of "Layer test". Statement (II) : "Layer test" to identify Br_2 and I_2 in aqueous solution involves the oxidation of bromide or iodide into Br_2 or I_2 respectively with Cl_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 :
A. Both Statement I and Statement II are true
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^- 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
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