CHEMICAL TESTS

• KEY SUBSTANCES TO IDENTIFY?

  • alkene
  • halogenoalkane
  • alcohol
  • aldehyde
  • carboxylic acid
• FUNCTIONAL GROUP OF AN ALKENE?

  C=C
• GENERAL FORMULA OF A HALOGENOALKANE?

  R-X
• GENERAL FORMULA OF AN ALCOHOL?

  R-OH
• GENERAL FORMULA OF AN ALDEHYDE?

  R-CHO
• GENERAL FORMULA OF A CARBOXYLIC ACID?

  R-COOH
• REAGENT USED TO TEST FOR AN ALKENE?

  bromine water
• TEST FOR ALKENES?

  shake with bromine water
• POSITIVE RESULT FOR A BROMINE WATER TEST ON AN ALKENE?

  orange colour disappears (becomes colourless)
• REAGENTS REQUIRED TO TEST A HALOGENOALKANE?

  NaOH, HNO3, AgNO3
• TEST FOR HALOGENOALKANES?

  1. Add NaOH (aq) and warm
  2. Acidify with HNO3
  3. Add AgNO3 (aq)
• POSITIVE RESULT OF A SILVER NITRATE TEST FOR HALOGENOALKANES?

  AgX precipitate
• WHAT COLOUR PRECIPITATE DOES CHLORINE IONS PRODUCE?

  white
• WHAT COLOUR PRECIPITATE DO BROMINE IONS PRODUCE?

  very pale cream
• WHAT COLOUR PRECIPITATE DO IODINE IONS PRODUCE?

  very pale yellow
• REAGENT TO TEST FOR ALCOHOLS?

  acidified K2Cr2O7
• TEST FOR ALCOHOLS?

  add acidified K2Cr2O7
• POSITIVE RESULT FOR ACIDIFIED K2CR2O7 TEST ON ALCOHOLS?

  orange colour turns green
• WHEN WILL THE ACIDIFED K2CR2O7 TEST HAVE A POSITIVE RESULT?

  primary/ secondary alcohols and aldehydes
• WHAT ION CAUSES THE ORANGE COLOUR OF ACIDIFED K2Cr2O7?

  Cr (+6)
• WHAT ION CAUSES THE GREEN COLOUR OF ACIDIFED K2Cr2O7?

  Cr (+3)
• REAGENT FOR TESTING FOR ALDEHYDES?

  Fehling's solution/ Tollens' solution
• TEST FOR ALDEHYDES?

  warm with Fehling's solution/ Tollens' solution
• POSITIVE RESULT FOR ALDEHYDE TEST (FEHLING'S SOLUTION)?

  blue colour turns to red precipitate
• POSITIVE RESULT FOR ALDEHYDE TEST (TOLLENS' SOLUTION)?

  silver mirror forms
• REAGENT FOR CARBOXYLIC ACID TEST?

  NaHCO3 (aq)
• TEST FOR CARBOXYLIC ACIDS?

  add NaHCO3 (aq)
• POSITIVE RESULT FOR TEST FOR CARBOXYLIC ACID?

  CO2 given off