Quiz 8 Flashcards
How do you calculate the index of hydrogen deficiency?
= (2C + 2 - H)/2
- add 1 to numerator for every N/P
- subtract 1 to numerator for every halogen
- ignore Oxygen/Sulfur
What does Beilstein Test test for?
Presence of Halogen
What does Benedict’s Test test for?
Presence of reducing carbohydrates/hemiacetals
What does the Bicarbonate Test test for?
Presence of Carboxylic Acids and Sulfonic Acids
What does the Bromine Test test for?
Unsaturation (not aromatics)
What does the Jones Test test for?
Aldehydes, primary alcohols, secondary alcohols
What does the 2,4-DNPH/Brady’s Test test for?
Aldehydes and Ketones
What does the Ferric Hydroxamate Test test for?
Esters
What does the Iodoform Test test for?
Methyl ketones or secondary alcohols next to a methyl group
What does the Lucas Test test for?
tertiary and secondary alcohols
What does the Permanganate/Baeyer Test test for?
Unsaturation
What does the pH test test for?
Carboxylic and Sulfonic acids
What does the Phenol Test test for?
phenols
What does the silver nitrate test test for?
tertiary and secondary alkyl halides
What does the Sodium Iodide/Finkelstein Test test for?
some alkyl chlorides and bromides (primary and secondary)
What does the Tollens Test test for?
Aldehydes
What does the Semicarbazone Test test for?
Aldehydes and Ketones
What is the mechanism of the Jones test?
- CrO3 in H2SO4
- aldehydes, primary alcohols, and secondary alcohols: positive
- tertiary alcohols: negative
- Positive: Orange Cr6+ reagent becomes blue-green Cr3+ and precipitates in acetone
- Negative: Orange remains orange
- Primary alcohol becomes carboxylic acid
- Secondary alcohol becomes ketone
- Aldehyde becomes carboxylic acid
What is the mechanism of the Tollens test?
- Reagent Ag(NH3)2+ oxidizes aldehydes
- Positive: formation of elemental silver/black colloidal precipitate
- Negative: no formation of precipitate
- Aldehyde becomes carboxylate anion
What is the mechanism of the Lucas Test?
- Reagent: concentrated HCl and ZnCl2
- Alcohols react to produce alkyl halides that are insoluble in aqueous solution
- Positive: cloudiness
- Negative: clear
- Tertiary alcohol react immediately
- Secondary Alcohol reacts more slowly
- Primary alcohols don’t react
- Benzylic alcohols, allylic alcohols give immediate results
- Phenols don’t react
What is the mechanism of the Phenol/FeCl3 test?
- Reagent: ferric chloride solution (FeCl3)
- Positive: dark blue, purple, red, green; phenols form intensely colored complexes with Fe3+
- Negative: yellow (fe3+ color)
What is the mechanism of the Baeyer test?
- Reagent: KMnO4
- positive: deep purple reagent reduced to brown precipitate (MnO2)
- Negative: deep purple with no precipitate
- Alkene becomes doubly substituted alcohol
- Aldehyde becomes carboxylic acid
What is the mechanism of the Iodoform test?
- Reagent: Iodine (I2) and Iodide (I-) in NaOH
- Positive: formation of canary yellow precipitate or cloudy yellow solution
- Negative: clear, yellow, or orange solution with no precipitate
- primary alcohols and methyl ketones become carboxylate anions
What is the mechanism of the semicarbazone test?
- reagent: semicarbazide hydrochloride
- positive: formation of semicarbazone, and if product has a different melting point than original compound
- negative: no formation of semicarbazone, and if product has the same melting point as the original compound
