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Zorluk: OrtaAlkanals and Alkanones: Oxidation, Reduction, and Distinction Tests

Match each chemical transformation or test involving alkanals and alkanones with its corresponding observation or principal product.

  • Oxidation of propanal with acidified K2Cr2O7K_2Cr_2O_7Color change from orange to green yielding propanoic acid
  • Reduction of propanone using LiAlH4LiAlH_4Formation of a secondary alcohol, propan-2-ol
  • Warming ethanal with Tollen's reagentDeposition of a shiny silver mirror coating
  • Warming propanone with I2I_2 in aqueous NaOHNaOHFormation of a characteristic yellow precipitate of triiodomethane (CHI3CHI_3)

Cevap

Oxidation of propanal with acidified K2Cr2O7K_2Cr_2O_7 matches color change from orange to green yielding propanoic acid; Reduction of propanone using LiAlH4LiAlH_4 matches formation of a secondary alcohol, propan-2-ol; Warming ethanal with Tollen's reagent matches deposition of a shiny silver mirror coating; Warming propanone with I2I_2 in aqueous NaOHNaOH matches formation of a characteristic yellow precipitate of triiodomethane (CHI3CHI_3).
Each chemical process uniquely corresponds to its diagnostic observation or reaction outcome: propanal oxidizes to propanoic acid with an orange-to-green color change (Cr3+Cr^{3+}); propanone reduces to propan-2-ol; ethanal reduces Tollen's reagent to produce a silver mirror; and propanone gives a positive iodoform test producing yellow CHI3CHI_3 precipitate.

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1
Analyze the oxidation reaction of propanal
Propanal is an alkanal oxidized by acidified dichromate to propanoic acid (CH3CH2COOHCH_3CH_2COOH) with dichromate reducing from orange Cr2O72−Cr_2O_7^{2-} to green Cr3+Cr^{3+}.
Alkanals are readily oxidized to alkanoic acids.
2
Determine the product of propanone reduction
Reducing propanone (CH3COCH3CH_3COCH_3) with LiAlH4LiAlH_4 adds hydrogen across the carbonyl double bond, converting the ketone into propan-2-ol (CH3CH(OH)CH3CH_3CH(OH)CH_3).
Reduction of alkanones yields secondary alcohols.
3
Evaluate the reaction between ethanal and Tollen's reagent
Ethanal oxidizes to ethanoic acid while reducing Ag+Ag^+ ions in ammoniacal silver nitrate to elemental silver metal (AgAg), depositing as a silver mirror.
Tollen's reagent specifically distinguishes alkanals from alkanones.
4
Analyze the iodoform test for propanone
Compounds containing the CH3C=OCH_3C=O group react with iodine in sodium hydroxide solution to yield triiodomethane (CHI3CHI_3), a yellow precipitate.
Propanone is a methyl ketone which gives a positive triiodomethane test.

Anahtar Kavram

Reactions and Distinction Tests of Alkanals and Alkanones
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Alkanals and Alkanones: Oxidation, Reduction, and Distinction Tests

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