6

• What is the first step in testing for an alcohol using metallic sodium?

  Add a small piece of metallic sodium
• What gas is produced when metallic sodium reacts with alcohol?

  Hydrogen gas
• How is the presence of hydrogen gas indicated in the alcohol test?

  By the 'squeaky pop' test
• How should excess sodium be disposed of after testing for alcohol?

  Using the beaker of ethanol provided
• Why is it dangerous for sodium to come into contact with water?

  It poses a serious fire risk
• What is added to determine between different types of alcohols?

  Acidified potassium dichromate
• What color change indicates the presence of primary or secondary alcohols when using potassium dichromate?

  From orange to green
• What color will the solution remain if a tertiary alcohol is present?

  Orange
• What is the first step in testing for an aldehyde using Fehling's solution?

  Mix equal volumes of Fehling's solution A and B
• What color is the resultant Fehling's test reagent?

  Clear dark blue
• How long should the aldehyde be warmed in the Fehling's test?

  For around two minutes
• What indicates the presence of an aldehyde after the Fehling's test?

  A brick red precipitate forms
• What is the first step in testing for an alkene using bromine water?

  Add about 1 cm​3​ of bromine water
• What happens to bromine water if an alkene is present?

  It decolourises from orange
• What is the first step in testing for a carboxylic acid using sodium carbonate?

  Place a spatula of solid sodium carbonate in a test tube
• What gas is produced when dilute ethanoic acid reacts with sodium carbonate?

  Carbon dioxide (CO​2)
• What happens to limewater when CO​2 is bubbled through it?

  It turns cloudy
• What is the first step in testing for a halogenoalkane?

  Add 5 drops of 1-bromobutane to sodium hydroxide
• What occurs during the reaction of 1-bromobutane with sodium hydroxide?

  OH- ions replace the Br by nucleophilic substitution
• At what temperature should the test tube be warmed during the halogenoalkane test?

  Approximately 60°C
• Why is nitric acid added after warming the test tube in the halogenoalkane test?

  To remove carbonate and hydroxide impurities
• What precipitate forms when silver nitrate is added to the halogenoalkane test?

  Silver Bromide precipitate