Module 4: Section 2- Alcohols, Haloalkanes And Synthesis Flashcards by Shona Mallen

Alcohols
What is the functional group

-OH

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Alcohols
What’s the suffix for one alcohol

-ol

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Alcohols
What is the suffix for two alcohol

-diol

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Alcohols
What’s the prefix

Hydroxy-

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Alcohols
What are the three types of alcohol

Primary secondary and tertiary

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Alcohols
What’s a primary alcohol

1 carbon around the carbon of the OH group
(End of chain )

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Alcohols
Notation for a primary alcohol

1°

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Alcohols
What’s a secondary alcohol

2 carbon around carbon with OH group
(In chain)

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Alcohols
Notation for secondary alcohol

2°

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Alcohols
What is a tertiary alcohol

3 carbon around carbon with OH group
Branched

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Alcohols
Notation for tertiary alcohol

3°

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Alcohols
Are alcohols polar

Yes due to the electronegative hydroxyl group which pulls the electrons in the C-OH bond away from the carbon atom

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Alcohols
What type of IMF can alcohols form

Hydrogen bonds

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Alcohols
Compared to alkanes what is alcohols solubility like

High water solubility

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Alcohols
Why do alcohols have high water solubility

Hydrogen bonds form between the -OH and H2O so lets it mix freely

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Alcohols
What happens to water solubility as alchohl gets larger and why

Solubility decreases because most of the molecule is non polar so there’s less attraction for the polar H2O

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Alcohols
Do alcolhs have low or high melting and boiling points compared to alkanes and why

Hydrogen bonds formed between alcohols which are the strongest type of IMF and requires the most energy to overcome

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Alcohols
Are alcohol volatile

Relative low volatility compared to alkanes

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Reactions of alcohols
What is combustion

Burnt in oxygen

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Reactions of alcohols
What is produced in the combustion of alcohol

CO2 and H2O

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Reactions of alcohols
Why are alcohols more likely to undergo complete combustion in comparison to incomplete combustion that alkanes

Already have oxygen in structure

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Reactions of alcohols
Important to remember whilst balancing equation fo combustion

Oxygen atom in the alcohol

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Reactions of alcohols
What is dehydration

Removal of H2O

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Reactions of alcohols
In dehydration where is the H2O removed form

Loses the -OH and -H groups

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Reactions of alcohols What does dehydration produce

A new Alkene and water

Reactions of alcohols What type or reaction is dehydration

Elimination

Reactions of alcohols What is the conditions for dehydration

An acid catalyst and reflux (heat)

Reactions of alcohols What acid catalysts can be used for dehydration

Concentrated sulfuric acid or concentrated phosphoric acid

Reactions of alcohols How many products can be formed by dehydration

Often multiple as hydrogen can be removed from either side of -COH and EZ isomerism can be present

Reactions of alcohols What happens in a substitution reaction

-OH group substituted by a halide when reacted with compounds containing halide ions

Reactions of alcohols What formed in a substitution reaction with halide ion

Haloalkane

Reactions of alcohols How does an alcohol have to be heated for substitution and with what

Heated under reflux with sulfuric acid and a sodium halide

Reactions of alcohols For substitution when is hydrogen halide formed

In situ in the reaction

Reactions of alcohols For substitution what is the equation for when the hydrogen halide is formed egwith Br

NaBr + H2SO4 —> NaHSO4 + HBr

Reactions of alcohols For substitution what is the general reaction for just alcohol with hydrogen halide after being formed in situ

Alcohol + hydrogen halide —> haloalkane + water

Reactions of alcohols Overall general equation for substitution of alcohol

Alcohol + H2SO4 + NaBr —> haloalkane + H2O + NaHSO4

Reactions of alcohols What are the two methods to heat an alcohol for oxidation

Distillation Reflux

Reactions of alcohols What does distillation do

Heat gently and remove products as its formed

Reactions of alcohols What does distillation prevent

Further reaction of product

Reactions of alcohols What needs to be considered for distillation

How to heat organic substance as may be flammable

Reactions of alcohols How does reflux work

Substance evaporated then recondensed and returns back to substance in flask by continuous heating

Reactions of alcohols Why in reflux is the top open

So pressure doesn’t build up

Reactions of alcohols What does oxidation of a alcohol require

An oxidising agent

Reactions of alcohols What is an oxidising agent

Oxidise other species by gaining electrons and are reduced themselves

Reactions of alcohols How is oxidising agent shown in reactions

[o]

Reactions of alcohols What oxidising agent is used in oxidation

Acidified potassium dichromate

Reactions of alcohols What colour is acidified potassium dichromate

Orange then goes green when reduced

Reactions of alcohols How do you know when alcohol has been oxidised

When the oxidising agent is reduced and changes colour

Reactions of alcohols What happens if you partially oxidise a primary alcohol

Forms aldehyde on primary carbon

Reactions of alcohols To partially oxidise a primary alcohol what method should be used

Distillation

Reactions of alcohols What is formed if you fully oxidise a primary alcohol

Carboxylic acid

Reactions of alcohols To fully oxidise a primary alcohol what method should be used

Reflux

Reactions of alcohols Equation for partially oxidising a primary alcohol (but an-1-ol)

Butan-1-ol + [o] —> butanal + water

Reactions of alcohols Equation for fully oxidising porimary alcohol butan-1-ol

Butan-1-ol + 2[o] —> butanoic acid + water

Reactions of alcohols What is formed when secondary alcohol is oxidised

Forms ketone on secondary C

Reactions of alcohols What method is best to use to oxidise a secondary alcohol and why

Reflux so all compound reacted

Reactions of alcohols Equation of oxidising secondary alcohol but an-2-ol

Butan-2-ol + [o] —> butanone + water

Reactions of alcohols What happens when tertiary alcohol oxidised

No reaction and acidified potassium dichromate remains orange

Reactions of alcohols Why can’t tertiary alcohols be oxidised

Because C atom whcih has -OH group has 3 other C atoms bonded to it and no H atom, in oxidation the carbon atom with the -OH group b=must be able to release an attached atom to form double C=O bond, C-H bond easily broken but not C-C bond

Haloalkanes What are they

Compound containing carbon, hydrogen and at least one halogen

Haloalkanes Suffix for chlorine

Chloro-

Haloalkanessuffix for bromine

Bromo-

Haloalkanes Suffix for iodine

Iodo-

Haloalkanes Suffix for fluorine

Fluoro-

Haloalkanes What can they be classified as

Primary Secondary Tertiary

Haloalkanes What is a primary haloalkane

Halogen at end of chain C only attached to one other C

Haloalkanes What is a secondary haloalkane

Halogen in chain C attached to two other C

Haloalkanes What is a tertiary haloalkane

Halogen at a branch C attached to three C

Haloalkanes What bond is polar in haloalkanes

Carbon-halogen bond

Haloalkanes Why is the carbon-halogen bond polar

Halogens is more electronegative than carbon so electron pair in covalent bond is closer to halogen

Haloalkanes What is definition for nucleophile

Electron pair don’or

Haloalkanes What actually is a nucleopjhile

Atom or group which is attracted to a positive centre where is donates a pair of electrons to form a new covalent bond

Haloalkanes Where is a nucleophile attracted to on a haloalkane

Electron deficient slightly positive carbon atom

Haloalkanes Example of three nucleophile

:OH- H2O: :NH3

Haloalkanes What is nucleophilic substitution for a haloalkane

When haloalkane reacts with a nucleophile replaces the halogen in a substitution reaction

Haloalkanes] What does the rate of the nucleophilic substitution reaction depend on

Strength/length of the C-halogen bond

Haloalkanes Ranking for rate of substitution reaction for each halogen-carbon bond

C-I>C-Br>C-Cl>C-F

Haloalkanes In general, what is a hydrolysis reaction

Reaction involving water or aqueous solution of a hydroxide that causes breaking of a bond and molecule split into two products

Haloalkanes What happens in the hydrolysis of a haloalkane

Halogen atom replaced by an -OH group

Haloalkanes General equation for hydrolysis

Haloalkane + OH- —> alcohol + halide

Haloalkanes What is the process for hydrolysis (6)

1. Nucleophile (OH-) attracted to slightly + carbon atom on opposite side from halogen 2. Direction of attack minimises repulsion between nucleophile , -OH and delta- halogen 3. Lone pair of electrons on OH- is donated to the + on the delta + carbon atom 4. New bond formed between oxygen on OH- and carbon atom 5. Carbon-halogen bond breaks through heterolytic fission 6. Alcohol and halide ion formed

Haloalkanes Hydrolysis

LEARN MECHANISN

Haloalkanes Reagent needed for hydrolysis

NaOH

Haloalkanes Conditions needed for hydrolysis

Warm, aqueous

Haloalkanes Equation for hydrolysis of chloroethane

C2H5Cl + NaOH —> C2H5OH + NaCl

Haloalkanes What side of the haloalkane is a nucleophile added onto

Opposite halogen

Haloalkanes Practical for hydrolysis of haloalkanes method

Hydrolysis of haloalkanes Set up three test tubes as follows: Tube 1: Add 1 cm3 of ethanol and two drops of I-chlorobutane Tube 2: Add I cm3 of ethanol and two drops of I-bromobutane Tube 3: Add I cm3 of ethanol and two drops of I-iodobutane 2 Stand the test tubes in a water bath at 60 oc. 3 Place a test tube containing 0.1 mol drn-3 silver nitrate in the water bath and allow all tubes to reach a constant temperature. 4 Add lcm3 of the silver nitrate quickly to each of the test tubes. Immediately start a stop-clock. 5 Observe the test tubes for five minutes and record the time taken for the precipitate to form. .

Haloalkanes Practical for hydrolysis results

Chloro- form a white precipitate very slowly Bromo- forms cream precipitate moderately time Iodo- yellow precipitate very quickly

Haloalkanes For practical of hydrolysis How are the products identifies

Using silver nitrate

Haloalkanes Why does C-I bond hydrolyse the quickest

Weakens bond due to its bond enthalpy

Haloalkanes Why does the C-Cl bond hydrolyse the slowest

Strongest bond due to its bond enthalpy

Haloalkanes What maintains the ozone level for life on earth

The equilibrium

Haloalkanes Why are oxygen radicals present in the ozone layer

Uv light causes homoltic fission

Haloalkanes Equation for homolytic fission of oxygen

O2 -> 2 O

Haloalkanes What is the quilibrium equation to maintain ozone levels

O2 + O <=> O3

Haloalkanes What was originally used in fridges and why was it bad

NH3(l) was unhealthy

Haloalkanes What was found that could be used in fridges

CFCs

Haloalkanes What are CFCs

Chlorofluorocarbons

Haloalkanes Example of CFC

Freeon CCl2F2

Haloalkanes What are the three properties of CFCs

Volatile, non flammable and low toxicity

Haloalkanes What happened to the ozone layer in the 1990s

Depletion started

Haloalkanes Initiation equation for depletion of ozone using CF2CL2

CF2Cl2 –uv—> Cl. + CF2Cl.

Haloalkanes Propagation for depletion of ozone using CF2Cl2

1. Cl. +O3 —> ClO. + O2 2. ClO. + O —> O2 + Cl.

Haloalkanes Where does O cone from in the depletion if ozone

Already in the mixture from equilibrium

Haloalkanes What is the overall equation for depletion of ozone

O3 + O —> 2 O2

Haloalkanes Is CFCs rhe only way for depletion of ozone

Other radicals present can also break down ozone

Haloalkanes What radical often breaks down ozone

NO.

Haloalkanes What are NO. Radica,s formed from

Lightning storms and aircraft travel

Haloalkanes Propagation of depletion of ozone by NO. Radicals

NO. + O3 —> O2 + NO2. NO2. + O —> NO . + O2

Haloalkanes Overall equation for depletion of ozone for NO. Radicals

O3 + O —> 2 O2

Module 4: Section 2- Alcohols, Haloalkanes And Synthesis Flashcards

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