addition of organometallic reagents to aldehydes, ketones Tollens', Benedict's or Fehling's reagents add to carbonyl groups overview of ketones and aldehydes Tollens' reagent aldehydes and ketones Tollens' reagent geminal hydroxyl groups thioacetal addition of organometallic reagents to aldehydes, ketones Acetals are stable to base has been noted Aldehydes and Ketones acetals overview of ketones and aldehydes described noted earlier aldehydes and ketones