Compound Lucas Reagent Chromic acid

1-butanol (A)2-butanol (B)

2-methylpropan-2-ol (C)Phenol (D)Unknown (E)

Iron(III) chloride Water

pH=7pH=7

pH=7pH=4.5pH=7

Explain why phenol reacts with NaOH while it does not react with NaHCO3. .

Explain the difference in reaction of the compounds toward Lucas Reagent.

Explain the difference in reaction of the compounds with chromic acid.Suggest a test reagent for Phenol. Explain your choice briefly.

State TWO methods for the formation of each of the alkanols A-C and phenol. Account for the browning of an apple on exposure to air for some time.

• Alcohols are soluble in water. An alcohol has two parts: hydrophilic –OH group and hydrophobic hydrocarbon part. The large hydrocarbon in long-chain alcohols limits the aqueous solubility of such alcohols.

• Unlike alcohol, phenol is weakly acidic as the conjugate base is resonance-stabilized. However, its acidic strength is strong enough to neutralize OH- but not strong enough to neutralize NaHCO3. It cannot liberate CO2 from HCO3

-.

• Tertiary alcohols rapidly react with Lucas reagent to form tertiary chloride, which produces immediate turbidity in the reagent. Primary alcohols cannot form stable primary carbocation upon protonation with Lucas reagent and thus show very slow or negative Lucas test.

• Primary alcohols can be oxidized by acidified K2Cr2O7 or chromic acid to carboxylic acid. Secondary alcohols can be oxidized to ketone while tertiary alcohols can only be oxidized in severe conditions.

• Unlike alcohol, phenol gives violet coloration with neutral iron(III) chloride as a result of complex formation.

• Benzenesulphonic acid reacts with NaOH at 300oC to give phenol. Aniline reacts with HNO2 at 0oC to give stable aryl diazonium salt which easily gives phenol upon hydrolysis.

• Primary and secondary alcohols can be formed from the hydration of alkenes in acidic medium. They are also formed respectively from aldehyde and ketone by reduction with NaBH4. Tertiary alcohols are formed by the hydrolysis of tertiary chloride at lower temperatures.