Ozone layer depletion is maximum over: MCQ with Answer and Explanation

Explanation:
In BF₃, boron has 3 valence electrons and forms 3 covalent bonds with fluorine, resulting in only 6 electrons in its valence shell. It does not complete its octet, making it an electron-deficient molecule and a strong Lewis acid. NH₃, H₂O, and CH₄ all have complete octets.

Explanation:
Haber process: N₂ + 3H₂ ⇌ 2NH₃, conditions: 400-450°C, 200 atm, finely divided iron with promoters (K₂O, Al₂O₃). Pt is used in Ostwald process for HNO₃; V₂O₅ in Contact process for H₂SO₄.

Explanation:
Isotopes have identical atomic numbers (number of protons) but different mass numbers due to different numbers of neutrons. They have similar chemical properties but different physical properties like mass and density. Example: ¹²C and ¹⁴C, both have 6 protons.