Identification of Function Groups by Test-Tube Reactions ORGANIC Flashcards
What test tube reaction is used for alkenes?
Shake with bromine water
What result will alkenes give in test tube reaction?
Orange to colourless
What test tube reaction is used for alkenes?
Add aqueous sodium hydroxide and warm gently
Acidify with nitric acid
Add silver nitrate
What result will halogenoalkanes give in test tube reaction?
Coloured precipitate of AgX forms
What colour precipitate is AgCl?
White
What colour precipitate is AgBr?
Cream
What colour precipitate is AgI?
Yellow
What test tube reaction is used for alcohols?
Add acidified potassium dichromate solution
What result will alcohols give in test tube reaction?
Varies depending on alcohol type
What result will primary alcohol give in test tube reaction?
Orange turns to green
What result will secondary alcohols give in test tube reaction?
Orange turns to green
What result will tertiary alcohol give in test tube reaction?
No reaction or colour change
What test tube reaction is used for aldehydes?
Warm with Tollen’s reagent
OR
Warm with Fehling’s reagent
What result will aldehyde give in Tollen’s reagent?
Silver mirror forms
What result will aldehyde give in Fehling’s reagent?
Blue solution turns to red precipitate
What test tube reaction is used for carboxylic acids?
Add sodium hydrogen carbonate
What result will carboxylic acid give in test tube reaction?
CO₂ gas formed
What is mass spectroscopy?
Analytical technique used to identify unknown compounds
Describe process of mass spectroscopy.
Molecules in sample bombarded with high energy electrons which cause molecules to lose electron
Molecular ion can further fragment to new ions, molecules and radicals
Fragmented ions are accelerated by electric field and separated by deflecting into detector
What are fragmented ions separated on in mass spectrometry?
Mass to charge ratio
Which ions are detected first in mass spectroscopy?
Smaller and more positively charged
What does the base peak in mass spectroscopy correspond to?
The most abundant ion
What are isotopes?
Atoms of the same element that contain the same number of protons and electrons but a different number of neutrons
What is mass spectroscopy used to find?
Relative abundance of isotopes experimentally
