Misconception 1: "Normal rain is neutral (pH 7.0)." Correction: Normal rain is pH 5.6, slightly acidic due to dissolved CO2 forming carbonic acid. Only distilled/deionized water is pH 7.
Misconception 2: "HDPE and LDPE are made from different monomers." Correction: Both HDPE and LDPE use the SAME monomer (ethene, C=C). The difference is the polymerization conditions and catalyst, which determines chain structure (linear vs branched).
Misconception 3: "Nylon-6 and Nylon-6,6 are the same polymer." Correction: Nylon-6 (one monomer: caprolactam, ring-opening) and Nylon-6,6 (two monomers: hexamethylenediamine + adipic acid) are different polymers with different repeat units, though both are polyamides.
Misconception 4: "Dacron/PET is a polyamide like nylon." Correction: Dacron/PET is a polyESTER (–COO– linkage). Nylons are polyAMIDES (–CO–NH– linkage). Both are condensation polymers, but different classes.
Misconception 5: "Vulcanization makes rubber completely rigid (like Bakelite)." Correction: Vulcanization makes rubber HARDER and MORE ELASTIC (not rigid). S–S cross-links prevent irreversible chain slippage but still allow stretching and recoiling — the characteristic elastic behavior.
Misconception 6: "CFC destroys ozone directly." Correction: CFC molecules do NOT directly destroy ozone. CFC releases Cl• radicals under UV radiation; Cl• is the species that catalytically destroys O3. CFCs → Cl• → O3 destruction.
Misconception 7: "Cl• is consumed in ozone depletion." Correction: Cl• is a CATALYST — it is regenerated at the end of each catalytic cycle. One Cl• can destroy ~100,000 O3 molecules without being consumed.
Misconception 8: "Minamata disease is caused by cadmium." Correction: Minamata disease = Mercury (Hg) poisoning (methylmercury). Cadmium (Cd) causes Itai-Itai disease.
Misconception 9: "High BOD means clean water (lots of oxygen)." Correction: High BOD means MORE organic pollution (more O2 is consumed by bacteria decomposing the organic matter). Clean water: BOD < 5 ppm. Polluted: BOD > 17 ppm.
Misconception 10: "Photochemical smog contains SO2 as the primary pollutant." Correction: SO2 is the primary pollutant in London smog (classical smog). Photochemical smog's primary pollutants are NOx and VOCs from automobile exhaust; secondary pollutants are O3 and PAN.
Misconception 11: "All addition polymers are thermoplastic; all condensation polymers are thermosetting." Correction: This is NOT universally true. Bakelite (condensation) is thermosetting; Dacron and nylon (condensation) are thermoplastic. Classification into thermoplastic/thermosetting depends on cross-linking, not the polymerization type.
Misconception 12: "Gutta-percha is chemically different from natural rubber." Correction: Gutta-percha and natural rubber have IDENTICAL chemical formula (C5H8)n — both are polyisoprene. They differ ONLY in the geometric (cis-trans) configuration of the double bond: cis = natural rubber (elastic); trans = gutta-percha (hard).
Misconception 13: "The ozone hole is permanent and growing steadily." Correction: The ozone hole is SEASONAL (occurs over Antarctica in spring, September–October). Since the Montreal Protocol (1987) phased out CFCs, the ozone layer is slowly recovering and is expected to be fully restored by ~2050–2060.
Misconception 14: "Acid rain only damages buildings, not aquatic life." Correction: Acid rain has multiple effects: (1) Marble/limestone corrosion (buildings, monuments); (2) Lake acidification → kills fish and aquatic organisms; (3) Soil acidification → leaches nutrients → harms plants; (4) Corrosion of metals.
Misconception 15: "PHBV is a synthetic polymer like polythene." Correction: PHBV is a NATURAL polymer . It is a natural polyester that can be used as a biodegradable alternative to synthetic plastics.