Retro (Past 13 Year) IIT-JEE Advanced (D Block Elements) - JEE MCQ

KMnO₄ is itself a very strong oxidising agent, O₃ cannot oxidise it.

ln CuCI²,Cu²⁺ has d⁹ configuration, exhibit d-d transition and show colour.
Similarly, in VOCI₂, V⁴⁺ has d¹ configuration, can exhibit d-d transition and show colour.

Solubilities of silver halides in water decreases from fluoride (AgF) to iodide (Agl). Silver fluoride is readily soluble in water hence, when AgNO₃ solution is added to HF solution (HF being weak acid, its solution maintain very low concentration of F^-) no precipitate of AgF is formed.
HCl, HBr and HI being all strong acid, forms precipitates of AgCI, AgBr and Agl when AgNO₃ solution is added to their aqueous solution.

The solubilities decreases from AgCI to Agl, AgCI dissolves in aqueous ammonia, AgBr dissolves only slightly in concentrated ammonia while Agl does not dissolve in ammonia solution. Na₂S₂O₃ solution dissolve all three, AgCI, AgBr, Agl by forming complex [Ag(S₂O₃)₂]^3- as is a stronger complexing agent than ammonia.

Acidified K₂Cr₂O₇, CuSO₄, H₂O₂, Cl₂, O₃, FeCI₃ and HNO₃ oxidise aqueous iodide to iodine. Alkaline KMnO₄ oxidise aqueous iodide to 
Na₂S₂O₃ is a strong reducing agent which on reaction with I₂ produces I^-.
Na₂S₂O₃ + I₂ → 2I^- + Na₂S₄O₆
Therefore, no reaction takes place between Na₂S₂O₃ and iodide ion.