Alcohols. Recap: ï‚› Acidity of ethanol and water ï‚› Video...
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Alcohols Recap: Acidity of ethanol and water Video Video Acidity of ethanol and 2-chloroethanol Preparation of Alcohols Method 1 Electrophilic Addition followed by Hydrolysis (laboratory method) CH 3 CH=CHCH 3 Preparation of Alcohols Method 2 (industrial method) Preparation of Alcohols NUCLEOPHILIC SUBSTITUTION OF HALOGENOALKANES CH 3 CHBrCH 2 CH 3 Preparation of Alcohols REDUCTION OF CARBOXYLIC ACIDS, ALDEHYDES OR KETONES LiAlH 4 in dry ether Reactions of Alcohols with Na with RCOOH with HX / PX 3 with conc. H 2 SO 4 COMBUSTION With a good supply of air, alcohols burn with a pale blue (non-luminous) flame to give carbon dioxide and water. C 2 H 5 OH(l) + 3O 2 (g) 2CO 2 (g) + 3H 2 O(l) FISSION OF ROH BOND with Na with RCOOH REACTIONS INVOLVING FISSION OF ROH BOND Reaction with sodium (Redox reaction or Acidmetal reaction) Effervescence observed. Gas extinguished a lighted splint with a pop sound. C 3 CH 2 O Na CH 3 CH 2 OH + Na + H 2 Esterification (Condensation reaction Try Fission of R-OH bond with HX / PX 3 with conc. H 2 SO 4 REACTIONS INVOLVING FISSION OF ROH BOND Note: VIDEOVIDEO Observations: Steamy white fumes of HC l produced. This is often used as a distinguishing test for the presence of the OH group in alcohols and carboxylic acids. Anhydrous condition must be used as PX 3, PX 5 and SOC l 2 reacts readily in water DEHYDRATION (ELIMINATION REACTION) majorminor Oxidation Observations: Orange K 2 Cr 2 O 7 turns green Purple KMnO 4 decolourises Tertiary alcohols are resistant to oxidation. Oxidation can be used as a test to distinguish tertiary alcohols from primary and secondary alcohols. VIDEO TRIIODOMETHANE (IODOFORM) TEST (OXIDATION) Yellow ppt of tri-iodomethane (iodoform) are formed.