The ONO angle is maximum in

Step-by-step solution

The nitrate ion has three resonance structure, with the double bond on a different oxygen for each. In all resonance structures the nitrogen has three bonds, therefore, its hybridisation is s p^2 . Each of the oxygen atoms also has s p^2 hybridisation, since the hybridisation is determined by the resonance structure with the double bond, where the oxygen has a double bond and two lone pairs. The actual geometry of the polyatomic ion is trigonal planar with bond angles of 120^ . NO ₂⁻: 18 electrons; ideal geometry t