MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

Ionization isomerism occurs when a ligand inside the coordination sphere is exchanged with an anion outside the coordination sphere (counter ion), resulting in a complex that yields different ions in solution. In the given complex [ Cr ( H _2 O )_4\, Cl ( NO _2)]\, Cl , the counter ion is Cl ^- and the ligands are H _2 O , Cl ^-, and NO _2^-. By exchanging the NO _2^- ligand inside the coordination sphere with the Cl ^- counter ion outside, we get the ionization isomer [ Cr ( H _2 O )_4\, Cl _2]\,( NO _2). The original complex yields Cl ^- ions in aqueous solution, whereas its ionization isomer yields NO _2^- ions. Answer: [ Cr ( H _2 O )_4\, Cl _2]\,( NO _2)