MHT CET Chemistry Question (2026) — Solution

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p-Nitrophenol has the highest melting point among the given compounds. In p-nitrophenol, there is strong intermolecular hydrogen bonding between the -OH group of one molecule and the -NO_2 group of another molecule. This leads to the association of molecules, requiring more thermal energy to break the crystal lattice. In contrast, o-nitrophenol exhibits intramolecular hydrogen bonding (chelation), which restricts molecular association and lowers its melting point. Phenol and p-cresol also exhibit intermolecular hydrogen bonding, but the interactions are weaker compared to p-nitrophenol. Additionally, the highly symmetrical structure of p-nitrophenol allows it to pack more efficiently in the solid state, further increasing its melting point. Answer: p-Nitrophenol