Unit 4 Flashcards by Sophie Cooper

Describe the Tollens test and result

Add aqueous sodium hydroxide to silver nitrate to form Silver (1) Nitrate. Redissolve in aqueous ammonia. Add aldehyde then warm in hot water bath.
Positive result =
Silver mirror Ag+ –> Ag

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Describe the Fehling’s test and result

Fehling’s A and Fehling’s B are mixed to form copper (11) complex (blue). If an aldehyde is added, a red-orange ppt of copper (1) oxide is formed.

Positive result =
blue –> red-orange Cu2+ –> Cu+

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Describe the Brady’s (2,4-DNPH) test and result

Add carbonyl to Brady’s reagent. A small amount of Sulfuric acid can be added to allow for precipitation.

Positive result =
Orange ppt formed (DNPH derivative formed)

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How to identify specific carbonyl after Brady’s test

Filter off precipitate (DNPH derivative), recrystallise, obtain melting point and compare to database values.

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Describe the iodoform test and result

Add aqueous iodine to compound containing COCH3. Add dilute sodium hydroxide until brown colour discharged. Warm gently then allow to cool.

Positive result =
yellow crystal ppt (triiodomethane)

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What is triiodomethane and its uses? (3)

Also known as Iodoform.
The yellow crystal ppt formed in the Iodoform reaction.
Used as antiseptic on plasters to treat minor cuts

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Type of reaction, reagents and conditions for Alkane to Halogenoalkane?

Free Radical Substitution
Cl₂
UV light

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What is the purpose of UV light in free radical substitution?

Breaks down the Cl₂ bonds producing free radicals.

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Type of reaction, reagents and conditions for Alkene to Alkane?

Hydrogenation
H₂, Ni Catalyst
Heat

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Type of reaction, reagents and conditions for Alkene to Halogenoalkane?

Electrophilic Addition
Halogen/ Hydrogen Halide

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Type of reaction, reagents and conditions for Alkene to Alcohol?

Dehydration
Acid Catalyst (H₃PO₄)
Heat/Reflux

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Type of reaction, reagents and conditions for Alcohol to Alkene?

Hydration
Acid Catalyst (H₃PO₄)
Heat/Steam

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Type of reaction, reagents and conditions for Alcohol to Halogenoalkane?

Nucleophilic Substitution
Na(X) + H₂SO₄
Heat/Reflux

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Type of reaction, reagents and conditions for Halogenoalkane to Alcohol?

Nucleophilic Substitution
NaOH
Heat/Reflux

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Type of reaction, reagents and conditions for Halogenoalkane to Nitrile?

Nucleophilic Substitution
KCN
Dissolved in ethanol

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Type of reaction, reagents and conditions for Halogenoalkane to Primary Amine?

Nucleophilic Substitution
R - Cl with NH₃
Dissolved in ethanol

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Type of reaction, reagents and conditions for Nitrile to Primary Amine?

Reduction
LiAlH₄
Dry Ether

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Type of reaction, reagents and conditions for Primary Amine to Secondary/Tertiary Amine?

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Type of reaction, reagents and conditions for Primary Amine to Amide?

Condensation
add Carboxylic Acid
Heat

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Type of reaction, reagents and conditions for Alcohols to Aldehydes?

Oxidation
H⁺/Cr₂O₇²⁻
Heat/Distil

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Type of reaction, reagents and conditions for Aldehydes to Alcohols?

Reduction
NaBH₄
Reflux

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Type of reaction, reagents and conditions for Nitrile to Carboxylic acid?

Acid Hydrolysis
H⁺/H₂O (H⁺ from HCl)

Type of reaction, reagents and conditions for Alcohol to Carboxylic acid?

Oxidation
H⁺/Cr₂O₇²⁻
Heat/Reflux

Type of reaction, reagents and conditions for Carboxylic acid to Alcohol?

Reduction
LiAlH₄
Ethoxyethane (Dry ether)

Type of reaction, reagents and conditions for Aldehyde to Carboxylic Acid?

Oxidation H⁺/Cr₂O₇²⁻

Type of reaction, reagents and conditions for Acyl-chloride to Amide?

Condensation NH₃ Heat

Type of reaction, reagents and conditions for Acyl-chloride to Carboxylic Acid?

Nucleophilic addition Elimination Hydrolysis - H₂O

Type of reaction, reagents and conditions for Carboxylic Acid to Acyl-chloride?

PCl₅ Dry Ether

Give the equation for making Acyl-chloride.

CH₃COOH + PCl₅ --> CH₃COCl + POCl₃ + HCl

Type of reaction, reagents and conditions for Aldehyde to Hydroxy Nitrile?

Nucleophilic addition HCN/H⁺ (aq)

Type of reaction, reagents and conditions for Acyl-chloride to Ester?

Esterification Conc. H₂SO₄ + Alcohol Reflux

Type of reaction, reagents and conditions for Carboxylic Acid to Ester?

Esterification Conc. H₂SO₄ + Alcohol Reflux

Type of reaction, reagents and conditions for Hydroxy Nitrile to Carboxylate?

Base Hydrolysis OH⁻/H₂O (OH⁻ from NaOH)

Type of reaction, reagents and conditions for Acid Anhydride to Ester?

Warm NaOH + Alcohol

Type of reaction, reagents and conditions for Ester to Carboxylate?

Base Hydrolysis NaOH

What is the primary structure of a peptide?

The sequence of amino acids.

What is the secondary structure of a peptide?

Either Alpha Helix or β-Pleated Sheet caused by Hydrogen bond formation.

What is the tertiary structure of a peptide?

Folds within the secondary structure caused by Ionic bonds, disulphide bridges ect...

What is the isoelectric point of an amino acid?

The pH point where it appears as a zwitter ion.

What does an amino acid act as when below the isoelectric point?

Excess H⁺ in solution so NH₂ becomes NH₃⁺ Therefore acts as a base

What does an amino acid act as when above the isoelectric point?

Excess OH⁻ in solution so COOH becomes COO⁻ Therefore acts as an acid

State the reagents, conditions and observations to test for an acid.

Add Sodium Carbonate at room temperature Effervescence, colourless gas

State the reagents, conditions and observations to test for a primary/secondary alcohol.

Add acidified sodium dicromate, Heat Orange --> Green

State the reagents, conditions and observations to test for an alkene.

Add bromine water at room temperature. brown ---> coulourless

State the reagents, conditions and observations to test for ANY alcohol.

Add solid phosphorus pentachloride, room temperature. vigorous reaction clouds of misty HCl gas

State the reagents, conditions and observations to test for phenol.

Add Iron(iii) chloride solutiom, room temperature. Purple colouration

State the reagents, conditions and observations to test for a primary amine.

Add nitric (iii) acid, room temp. Effervescence, colourless gas

State the reagents, conditions and observations to test for a secondary amine.

Add nitric (iii) acid, room temp. Yellow oil (nitrous amine)

State the reagents, conditions and observations to test for a tertiary amine.

Add nitric (iii) acid, room temp. colourless solution ( the amine forms an ion)

What is the yellow oil formed when testing for a secondary amine?

Nitrous amine - a powerful carcinogen.

What does chlorine look like at room temperature and in solution?

Pale green gas Pale green in solution

What does bromine look like at room temperature and in solution?

dark red - brown liquid Orange in solution

What does iodine look like at room temperature and in solution?

grey-black solid that can sublime to purple vapour. Dark brown in solution.