An ion/compound possessing a lone pair of electrons that seek out a relatively positive site. They donate an electron pair.
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Electrophile
An ion or compound possessing vacant orbitals that seek out a relatively negative site.
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Heterolytic bond fission
The uneven splitting of a bond in which one of the bonded atoms receives both the bonded electrons.
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There are two common methods to form an alcohol. Name these two methods.
1. From halogenoalkanes by nucleophilic substitution. 2. By reducing aldehydes, ketones or c.acids.
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How do we test for alcohols?
LUCAS TEST (zinc chloride in concentrated HCl). Secondary alcohols will form cloudiness.
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Nucleophilic substitution of halogenoalkanes - conditions?
Aqueous NaOH and reflux.
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Reduction of carbonyl compounds - conditions?
For aldehydes and ketones, sodium borohydride. For c.acids, the stronger reducing agent lithium aluminium hydride.
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Why is the ethanoylation of alcohols by nucleophilic addition elimination an important reaction?
1. It gives a better yield of ester than esterification. 2. The addition of another carbon atom increases the number of further reactions.
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When is DILUTE AMMONIA added?
To distinguish between Br- and Cl-. The Cl- completely dissolves.
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When is CONCENTRATED AMMONIA added?
To distinguish between Br- and I-. The I- dissolves.
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What colour does potassium dichromate turn when added to primary and secondary alcohols?
Orange → green
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What colour does potassium permanganate turn when added to primary and secondary alcohols?
Purple → brown
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What is phenol?
A toxic crystalline solid.
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Phenol acts as a...
Weak acid, and so partially dissociates in water to form the phenoxide ion, which is stabilised by the delocalisation of electrons.
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Phenol is a stronger acid than (1) but a weaker acid than (2).
1. Ethanol. 2. Ethanoic acid
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Explain the acidity of phenol.
One of the lone pairs of the oxygen atom can overlap with the delocalised pi electron ring to form an extended delocalised system. As a result the C-O bond is shorter and STRONGER. This makes C-O bond fission harded.
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Acidity of phenol continued...
This extended delocalisation creates a higher electron density in the ring and makes the hydrogen of the OH more 'acidic' - more available to be donated.
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As phenol acts as a weak acid it can react with a...
BASE
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How would you distinguish between phenol and a carboxylic acid?
1. Dissolve phenol in water. 2. Add sodium carbonate. The c.acid will produce effervescence.
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How to distinguish between phenol and an alcohol?
You can add bromine water, as phenols will produce a white ppt.
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Ethanoylation of phenols - conditions?
Base, such as pyridine.
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Other cards in this set
Card 2
Front
Electrophile
Back
An ion or compound possessing vacant orbitals that seek out a relatively negative site.
Card 3
Front
Heterolytic bond fission
Back
Card 4
Front
There are two common methods to form an alcohol. Name these two methods.
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