Error 1: "All HX react anti-Markovnikov with peroxide." FIX: Only HBr + organic peroxide gives anti-Markovnikov addition. HCl fails (endothermic Cl• + alkene step). HI fails (premature chain termination). This is the single highest-frequency NEET trap.

Error 2: "Lindlar's catalyst gives trans-alkene from alkynes." FIX: Lindlar's → cis-alkene (syn-addition). Na/liq. $NH_{3}$ → trans-alkene (anti-addition). Mnemonic: Lindlar = "L for cis (sis = same side)"; Na/$NH_{3}$ = "N for trans (not same side)".

Error 3: "The gauche conformation is the least stable in butane." FIX: Fully eclipsed (0° dihedral, $CH_{3}$ eclipsing $CH_{3}$) is the least stable (~19 kJ/mol above anti). Gauche is only ~3.8 kJ/mol above anti. The eclipsed (120°) is at ~16 kJ/mol — between gauche and fully eclipsed.

Error 4: "Ozonolysis always gives carboxylic acids." FIX: Reductive workup (Zn/$H_{2}O$) gives aldehydes/ketones. Oxidative workup ($H_{2}O$_{2}) gives carboxylic acids (from the aldehyde fragment). The NEET standard is the reductive workup.

Error 5: "$sp^{3}$ C–H bonds are most acidic because $sp^{3}$ is most common." FIX: $sp^{3}$ C–H bonds are LEAST acidic (25% s-character, pKa ~50). sp (alkyne) is most acidic (50% s-character, pKa ~25). Acidity correlates with s-character, not abundance.

Error 6: "Free radical termination regenerates X• radicals." FIX: Termination DESTROYS radicals (radical + radical → stable molecule). Only propagation steps generate new radicals (X• is regenerated in propagation step 2: R• + $X_{2}$ → R–X + X•).

Error 7: "Gauche and anti are both eclipsed conformations." FIX: Gauche (60°) and anti (180°) are both STAGGERED conformations — the bonds are offset, not aligned. Eclipsed (0°, 120°, 240°) conformations have aligned bonds.