Compounds containing Carbonyl group

• What are carbonyls?

  Carbonyls are compounds with a C=O bond.
• How can you differentiate between aldehydes and ketones based on the C=O bond position?

  If the C=O is at the end of the chain, it is an aldehyde; if in the middle, it is a ketone.
• What is the suffix used for naming aldehydes?

  The name will end in –al.
• What is the suffix used for naming ketones?

  The name will end in –one.
• What is the chemical formula for ethanal?

  CH3CHO.
• What is the chemical formula for propanone?

  CH3COCH3.
• Why are smaller carbonyls soluble in water?

  Because they can form hydrogen bonds with water.
• How does the strength of the C=O bond compare to the C=C bond in alkenes?

  The C=O bond is stronger and does not undergo addition reactions easily.
• What type of intermolecular forces do pure carbonyls exhibit?

  Pure carbonyls are attracted by permanent dipole forces.
• Why is the C=O bond polarized?

  Because oxygen is more electronegative than carbon.
• What happens to primary alcohols during oxidation?

  They are oxidized to aldehydes and then to carboxylic acids.
• What happens to secondary alcohols during oxidation?

  They are oxidized to ketones.
• What happens to tertiary alcohols during oxidation?

  Tertiary alcohols do not oxidize.
• What is the role of potassium dichromate in oxidation reactions?

  Potassium dichromate is an oxidizing agent that causes alcohols and aldehydes to oxidize.
• What is the key point regarding the oxidation of aldehydes and ketones?

  Aldehydes can be oxidized to carboxylic acids, but ketones cannot be oxidized.
• What is the reaction equation for the oxidation of an aldehyde to a carboxylic acid?

  RCHO + [O] → RCO2H.
• What is the full equation for the oxidation of ethanal using potassium dichromate?

  3CH3CHO + Cr2O7^2- + 8H+ → 3CH3CO2H + 4H2O + 2Cr3+.
• What observation indicates the reduction of the orange dichromate ion during oxidation?

  The orange dichromate ion reduces to the green Cr3+ ion.
• What are Fehling’s solution and Tollen’s reagent used for?

  They are used as tests for the presence of aldehyde groups.
• What happens to copper (II) ions in Fehling’s solution when aldehydes are oxidized?

  The copper (II) ions are reduced to copper (I) oxide.
• What is the observation when aldehydes react with Fehling’s solution?

  Blue Cu2+ ions change to a red precipitate of Cu2O.
• What is the observation when aldehydes react with Tollen’s reagent?

  A silver mirror forms coating the inside of the test tube.
• What is the reaction of aldehydes with Tollen’s reagent?

  Aldehydes are oxidized to carboxylic acids while silver(I) ions are reduced to silver atoms.
• What is the reaction of carbonyls with hydrogen cyanide?

  Carbonyls react with hydrogen cyanide to form hydroxynitriles.
• What reagents are used in the reaction of carbonyls to form hydroxynitriles?

  Potassium cyanide (KCN) and dilute sulfuric acid.
• What is the mechanism of the reaction forming hydroxynitriles from carbonyls?

  The mechanism involves nucleophilic addition.
• How do you name hydroxynitriles?

  The CN becomes part of the main chain and carbon number 1.
• What is the advantage of using KCN or NaCN over HCN in reactions?

  KCN or NaCN provide a higher concentration of CN- ions as they completely ionize.
• What is the result of nucleophilic addition of HCN to unsymmetrical aldehydes and ketones?

  A racemate forms, resulting in no optical activity.
• What happens when HCN attacks the planar carbonyl group?

  HCN attacks equally from both sides, leading to the formation of a racemate.