3.8 Aldehydes and ketones

• Aldehydes and ketones have a carbonyl functional group, a C double bond O group.
• The difference between an aldehyde and a ketone is the position of that carbonyl group.
• For aldehydes, the carbonyl group is at the end of the carbon chain and it ends in OWL.
• Examples of aldehydes include propanol, methanol, propanol, butanol, and so on, all of which end in OWL.
• Ketones have the carbonyl group in the middle as it is, so they have a carbonyl group on the inner carbon and all the carbons end in OWL.
• Tollen's reagent is used to distinguish between aldehydes and ketones.
• The aldehyde group was sitting on the second carbon in the main carbon chain.
• The Tollen's reagent is used to distinguish between aldehydes and ketones.
• Silver nitrate is a colorless solution.
• To make Tollen's reagent, add silver nitrate to a test tube, add a few drops of sodium hydroxide, and dilute ammonia until a pale brown precipitate forms.
• Ketones are not oxidized at all and do not form anything.
• Aldehydes make carboxylic acids when oxidized with an oxidizing agent.
• If an aldehyde is present in a test tube, a silver mirror forms as a precipitate.
• Examples of ketones include propanone, methyl acetate, and so on, all of which end in OWL.
• The Tollen's reagent solution can also be used to distinguish between aldehydes and ketones, acting as an oxidizing agent to oxidize aldehydes but not ketones.
• Aldehydes can be reduced to primary alcohols using sodium borohydride as a reducing agent.
• Reducing agents can be represented with a H in square brackets, as it's the H minus iron that makes something a reducing agent.
• The transition metals video discusses the linear complex formed by Tollen's reagent.
• Aldehydes form a silver mirror when reacted with Tollen's reagent, while ketones do not.
• The failings solution contains copper two plus ions and changes from blue to brick red when an aldehyde is present.
• A large conical flask can be used to test the hands, with an aldehyde added and the Tollen's reagent mixed and swirled.
• Tollen's reagent is a silver complex with two ammonia ligands and is used to distinguish between aldehydes and ketones.
• Ketones remain blue in the failings solution, as they cannot be oxidized.
• When using potassium cyanide, if hydrogen cyanide is used to produce cyanide ions, no acid is needed because hydrogen cyanide produces H+ ions which makes it acidic.
• Potassium cyanide dissociates in acidic solution, forming a solution with K+ or a large amount of K+ in it and CN- in it.
• CN- comes from the potassium cyanide, it's a nucleophile because it's going to attack the Delta positive carbon and it has a lone pair of electrons that's the key factor there for a nucleophile.
• The double bond in the aldehyde or ketone is going to break and two of the electrons from that double bond are going to enter into the oxygen, forming an O- intermediate.
• Hydroxyl group in which is OH and it has a nitrile group in which is CN.
• Addition reaction, not a substitution.
• The generic equation for the reaction of an aldehyde or ketone with potassium cyanide is: aldehyde or ketone plus potassium cyanide plus h+ ions results in a hydroxy nitrile and potassium ions that are floating around.
• Potassium cyanide is used because it's easier to handle than hydrogen cyanide, which is gas and toxic.
• When using potassium cyanide, the lone pair of electrons on the oxygen go and attack the H+ ion that's floating around in solution, producing a hydroxy nitrile.
• If potassium cyanide is used to signify acidify the solution, a supply of H+ ions is available in that solution.
• Reducing agents contain hydride ions (H-) which can be used to reduce aldehydes and ketones through the alcohols.
• Reducing agents contain lone pair of electrons which they use to attack the Delta positive carbon, making them nucleophiles.
• Reducing agents contain lone
• The mechanism for reducing aldehydes and ketones involves a hydride ion (H-) attacking the Delta positive carbon, forming an intermediate, and then hydrogenating the intermediate to form an alcohol.
• All aldehydes produce primary alcohols and all ketones produce secondary alcohols.
• Aldehydes and ketones can be used to form primary and secondary alcohols.
• The mechanism for forming secondary alcohols from aldehydes and ketones involves a hydride ion (H-) attacking the Delta positive carbon, forming an intermediate, and then hydrogenating the intermediate to form an alcohol.