📦 haribo's chem notes,

chemical tests

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further chem
Fehling’s test tests for aldehyde

  • blue to red
  • from to

Tollens’ reagent ammoniacal silver nitrate tests for aldehyde

  • prepared from silver nitrate, sodium hydroxide, ammonia solution
  • positive observation: silver mirror formed

2-4,dinitrophenylhydrazine (brady’s reagent 2,4-DNPH) tests for carbonyls

  • positive observation: produces orange crystal
  • lone pair on (part of hydrazine) attacks electron-deficient carbon of carbonyl

and tests for presence of (carboxylic acids and 1Ëš and 2Ëš alcohols)

  • lone pair on oxygen attacks electron-deficient phosphorus(V) atom
    • because bond very strong
  • turns into good LG
  • SN2 substitution reaction after attached to phosphorus
  • observation: evolved, test with conc. for thick white fumes, and phosphorus oxychloride or

Alkaline aqueous iodine iodoform reaction tests for methyl ketones and secondary alcohols

  • positive observation: produces pale yellow precipitate

bubble gas through limewater tests for

  • positive observation: cloudy

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