Organic Analysis Flashcards
What is the test for primary and secondary alcohols?
Add potassium dichromate and if the solution goes from orange to green then an alcohol is present.
How does potassium dichromate work?
The orange dichromate is reduced into a green chromate 3+ ion and that oxidises the alcohol.
How do you test for primary alcohols?
- Add potassium dichromate and if it turns green then an alcohol is present.
- Distill the products as they are formed and if the product is an aldehyde then a primary alcohol is present.
- If you heat the solution under reflux and it tests positive for a carboxylic acid then you have a primary alcohol.
What is the test for an aldehyde?
Add Fehling’s reagent and if the blue solution turns into a red precipitate then an aldehyde is present. Add Tollen’s Reagent and if a silver mirror forms then an aldehyde is present.
What is the test for a carboxylic acid?
Add sodium carbonate and if you see fizzing then a carboxylic acid is present.
What is the test for secondary alcohols?
- Add potassium dichromate and it should turn green.
- Heat under reflux and if the product is a ketone then you have a secondary alcohol.
What is the test for a ketone?
Add Fehling’s and Tollen’s reagent and there will be no reaction.
What is the test for a tertiary alcohol?
Add potassium dichromate and it should remain orange.
What is the test for alkenes?
Add bromine water and shake. If the solution decolorises then an alkene is present.
What does m/z mean in mass spectroscopy?
The Mr or Ar.
How does infrared spectroscopy work?
When infrared radiation is passed through a chemical the covalent bonds absorb some of that energy which increases their vibrational energy. Bonds in between different atoms and in different places in a molecule absorb different frequencies of energy.
What is the fingerprint region?
The region above 1500 that is unique to every compound.
How do greenhouse gases cause global warming?
The bonds in the molecules of greenhouse gases absorb infrared radiation. This traps the energy inside the atmosphere and causes temperatures to increase.
