Error 1: Thinking Ketones Give Positive Tollens' Test

Wrong belief: "Acetone has a C=O group, so it will give a silver mirror." Correct fact: Tollens' oxidizes the aldehyde C-H bond; ketones have no such bond. Ketones do NOT give silver mirror. Trigger: When you see "C=O present → Tollens' positive" — WRONG. Must be an aldehyde.

Error 2: Confusing Clemmensen and Wolff-Kishner Products

Wrong belief: "Clemmensen gives alcohol, Wolff-Kishner gives hydrocarbon." Correct fact: BOTH give CH2 (complete deoxygenation). NaBH4/LiAlH4 gives alcohol (C-OH retained).

Error 3: Saying Benzaldehyde Undergoes Aldol Condensation

Wrong belief: "Benzaldehyde has an aldehyde group, so it gives aldol." Correct fact: Benzaldehyde has NO alpha-H (adjacent C is benzene ring carbon). It undergoes Cannizzaro, not aldol.

Error 4: Methanol Gives Positive Iodoform Test

Wrong belief: "Methanol is an alcohol, so it gives iodoform like ethanol." Correct fact: Methanol (CH3OH) is oxidized to HCHO (formaldehyde), which has no CH3CO- group. Iodoform test is NEGATIVE for methanol.

Error 5: 2,4-DNP Test Distinguishes Aldehydes from Ketones

Wrong belief: "2,4-DNP is positive for aldehydes, negative for ketones." Correct fact: 2,4-DNP is positive for ALL C=O-containing compounds (both aldehydes and ketones). It only detects C=O, not its type.

Error 6: Thinking NaBH4 Completely Removes Oxygen (Like Clemmensen)

Wrong belief: "NaBH4 and Clemmensen both remove the carbonyl oxygen." Correct fact: NaBH4 reduces C=O to C-OH (alcohol, oxygen retained). Clemmensen reduces C=O to CH2 (oxygen completely removed).

Error 7: Diethyl Ketone Gives Positive Iodoform

Wrong belief: "Diethyl ketone is a ketone and contains C=O, so it gives iodoform." Correct fact: Diethyl ketone (CH3CH2COCH2CH3) has NO CH3CO- group — both sides of C=O are ethyl. It does NOT give iodoform. Only methyl ketones (CH3CO-R) are iodoform-positive.

Error 8: Isopropanol Does Not Give Iodoform

Wrong belief: "Isopropanol is a secondary alcohol, not a methyl ketone. So no iodoform." Correct fact: Isopropanol (CH3CHOHCH3) is first oxidized to acetone (CH3COCH3) by I2/NaOH. Acetone is a methyl ketone → iodoform positive. The test can also oxidize secondary methyl carbinols.