Alcohol Phenol and Ether Class 12 Notes: CBSE Chemistry Chapter 7

Section – A (1 Mark Questions)

1. What is the IUPAC name of o-cresol ?

Ans. 2-Methylbenzenol

2. What is the formula of methoxyethane? 

Ans. CH3OCH2CH3

3. What is the IUPAC name of Picric acid?

Ans. 2,4,6-trinitrophenol (TNP)

4. Name the reagents used in the oxidation of primary alcohol to carboxylic acid

Ans. alkaline KMnO4

5. What is the general formula of monohydric alcohol ?

Ans. CnH2nOH

6. Phenol on distillation with zinc dust produces……….

Ans. Benzene

7. Dipole moment in ether is due to …..

Ans. The C - O bonds in the ether are polar and thus ethers have a net dipole moment.

8. Williamson’s synthesis is used to prepare………

Ans. Ether

9. What is the IUPAC name of C6H5-O-C2H5 ?

Ans. Ethoxy benzene

10. What is the IUPAC name of salicyclic acid?

Ans. 2-Hydroxybenzoic acid

Section – B (2 Marks Questions)

11. What is the class of compound formed by the substitution of a hydrogen atom in a hydrocarbon by an alkoxy or aryloxy group ?

Ans. The substitution of a hydrogen atom in a hydrocarbon by an alkoxy or aryloxy group               (R–O/Ar–O) yields another class of compounds known   as 'ethers', for example, CH3OCH3 (dimethyl ether).

12. What are the products formed by the mononitration of 3 – methylphenol?

Ans. OH and CH3 groups are ortho, and para–directing, so major products are

13. What are the gases released when p –nitrophenol react with NaHCO3?

Ans. 

14. What is the product formed when phenol reacts with Br2/H2O

Ans. 

15. Why are ethers relatively inert compounds ?

Ans. Ethers are inert compounds because the functional group of ethers (-O-) does not contain any active site. Therefore, under ordinary conditions, they are stable to bases, dilute acids and other oxidising and reducing agents.

16. Why ether is more volatile than alcohol  having same molecular mass ?

Ans. An ether is more volatile than alcohol having the same molecular formula. This is due to intermolecular hydrogen bonding in alcohols. In alcohols, H atom is attached to strongly electronegative O atom. Therefore, they exist as an associated molecule due to hydrogen bonding.

17. Write the product when ethanol react with conc. H2SO4 at 445 K

Ans. $CH_{3}-\underset{\text{Ethylalcohol}}{CH_2}-OH\xrightarrow[443K]{H_{2}SO_{4}}CH_{2_{Ethene}}=CH_{2}+H_{2}O$

18. What is the hybridisation of carbon and oxygen in ether?

Ans. 

19. Write the decreasing order of acidity of 1° alcohol, 2° alcohol and 3° alcohol .

Ans. An electron releasing group (CH3, C2H5) increases electron density on oxygen tending to decrease the polarity of OH bond. This decreases the acid strength. For this reason, the acid strength of alcohols decreases in the following order

PDF Summary - Class 12 Chemistry Alcohols, Phenols and Ethers Notes (Chapter 7)

1. Introduction

Alcohols are compounds that have a hydroxyl group  \[\left( {{\text{ - OH}}} \right)\]  attached to a saturated carbon atom. Enols are compounds that have a hydroxyl group attached to an unsaturated carbon atom of a double bond. The saturated carbon can be alkyl, alkenyl, alkynyl, cycloalkyl, or benzyl. If, on the other hand, a hydroxyl group is attached to a benzene ring. Phenols are the name given to these compounds.

The alcohols are further classified as monohydric (containing one  \[{\text{ - OH}}\]  group), dihydric (containing two  \[{\text{ - OH}}\]  groups), and trihydric (containing three  \[{\text{ - OH}}\]  groups) (containing three  \[{\text{ - OH}}\]  groups).

Alcohol is used in both industry and everyday life. Chiefly ethanol, for example, is a common spirit used to polish wooden furniture. Sugar, cotton, and paper are all composed of compounds that contain groups. Phenols are found in a variety of important polymers, including Bakelite, as well as pharmaceuticals such as Aspirin. Ethers are commonly used as anaesthetics and solvents.

In alcohols, the oxygen of the  group is attached to carbon by a sigma (  bond formed by the overlap of a sp hybridised forbital of carbon with a sp hybridised orbital of oxygen. The following figure depicts structural aspects of methanol, phenol and methoxymethane.

2. Classification

Classification of alcohols and symmetrical and unsymmetrical ether

3. Structure of Functional Groups

In the structure of alcohols, the oxygen of hydroxyl group is connected to carbon through a sigma bond which is formed by the overlapping of  \[\text{s}{{\text{p}}^{3}}\]  hybridised orbital of C with a  \[\text{s}{{\text{p}}^{3}}\]  hybridised orbital of oxygen. The structural aspects of phenol, methanol and methoxymethane are depicted by the following figure.

Structure of methanol

Due to lone pair-lone pair repulsion, bond angle is slightly less.

Structure of Phenol

Since a pair of oxygen is delocalised on the ring, the length of the  \[{\text{C - O}}\]  bond is reduced.

Structure of Methoxymethane

Due to the general repulsive interaction between the two bulky (R) groups, the bond angle in methoxymethane is greater than the tetrahedral angle. The length of the  \[{\text{C - O}}\] bond is the same as in alcohols.

4. Physical Properties

4.1 Boiling Point

The boiling points of alcohols and phenols rise as the number of carbon atoms increases (increase in van der Waals forces). The boiling point of alcohol decreases as branching increases (decrease in Van der Waals forces due to decrease in surface area). In alcohols and phenols, the -OH group contains a hydrogen atom that is bonded to an electronegative oxygen atom. As a result, it is capable of forming intermolecular hydrogen bonds with greater strength than amine.

Formation of intermolecular hydrogen bonds in alcohols and phenols

Alcohols and phenols have higher boiling points than other classes of compounds, such as hydrocarbons, ethers, and haloalkanes/haloarenes, amines with comparable molecular masses, due to the presence of strong intermolecular hydrogen bonding.

Their boiling points are lower than those of carboxylic acid, which has a stronger hydrogen bond. Boiling points for isomeric alcohols decrease as branching increases due to a decrease in van der Waals forces as size decreases. The boiling point sequence is primary alcohol > secondary alcohol > tertiary alcohol.

Due to lower dipole moment and the absence of H-bonding, the boiling point of ethers is very low and comparable to that of alkanes of comparable molecular mass.

4.2 Solubility 

Alcohols and phenols are soluble in water due to their ability to form hydrogen bonds with water molecules. Solubility decreases as the size of the hydrophobic group increases (R). Higher concentrations of alcohol are insoluble. Because of the decrease in surface area of the nonpolar hydrocarbon part, branching increases solubility.

n-butyl alcohol < isobutyl alcohol < sec-butyl alcohol < tert-butyl alcohol

Formation of hydrogen bonds Between alcohol and water

Lower ethers are water soluble, but their solubility is lower than that of alcohol due to less H-bonding with water and being less polar.

5. Preparation of Alcohols

Flow chart showing preparation of alcohols

5.1 Alkane

Controlled oxidation

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5.2 Alkenes

5.2.1 Acid Catalyzed Hydration

Markovnikov addition with carbocation rearrangements.

Reaction showing Acid Catalyzed Hydration of alkene

5.2.2 Oxymercuration-Demercuration

Markovnikov addition without carbocation rearrangements.

Example - 1

Reaction showing Oxymercuration-Demercuration

5.2.3 Hydroboration-Oxidation Anti-Markovnikov Addition.

Example-2

Reaction showing Hydroboration-Oxidation Anti-Markovnikov addition

5.2.4 SYN Hydroxylation

Reagents: Cold dil.  \[{\text{KMn}}{{\text{O}}_{\text{4}}}/{\text{NaOH or Os}}{{\text{O}}_{\text{4}}}/{{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}}\] 

Example-3

Reaction showing Syn Hydroxylation

5.2.5 ANTI Hydroxylation  

Reagents: Peroxy acids followed by acidic hydrolysis

Example-4

Reaction showing Anti Hydroxylation

5.3 Alkyl Halide

5.3.1 Second Order Substitution

Primary and some Secondary Halides

${{\left( \text{C}{{\text{H}}_{3}} \right)}_{2}}\text{CHC}{{\text{H}}_{2}}\text{C}{{\text{H}}_{2}}-\text{Br}\xrightarrow[{{\text{H}}_{2}}\text{O}]{\text{KOH}}{{\left( \text{C}{{\text{H}}_{3}} \right)}_{2}}\text{CHC}{{\text{H}}_{2}}\text{C}{{\text{H}}_{2}}-\text{OH}$

Example -6 

Reaction between tertiary butyl chloride and acetone

5.3.2 Grignard Reagent/ Organolithium Reagent

Nucleophilic addition to the carbonyl group

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1. Addition to Formaldehyde-primary alcohol 

Example-7 

Reaction showing addition of Grignard Reagent to Formaldehyde forming primary alcohol

2. Addition to aldehyde-secondary alcohol 

Example-8 

Reaction showing addition of Grignard Reagent to aldehyde forming a secondary alcohol

3. Addition to a ketone-tertiary alcohol 

Example-9 

Reaction showing addition of Grignard Reagent to a ketone forming a tertiary alcohol

4. Addition to an acid-halide or an Ester-tertiary alcohol

Example-10  Addition to an Acid Halide

$\mathrm{R}-\mathrm{CO}-\mathrm{X}+\left(\mathrm{R}^{\prime}\right)_{3} \mathrm{COH} \rightarrow \text { R-CO-O- }\left(\mathrm{R}^{\prime}\right)_{3}+\mathrm{HX} $

Addition to an Ester

$\mathrm{R}-\mathrm{CO}-\mathrm{O}-\mathrm{R} '+\left(\mathrm{R}^{\prime \prime}\right)_{3} \mathrm{COH} \rightarrow \mathrm{R}-\mathrm{CO}-\mathrm{O}-\left(\mathrm{R}^{\prime \prime}\right)_{3}+\mathrm{R}^{\prime}-\mathrm{OH}$

5. Addition to Ethylene oxide-primary alcohol (with two carbon atoms added)

Example-11

Ethylene oxide+R-CH2​OH→R-CH2​CH2​CH2​OH

5.4 Carbonyl Compounds

5.4.1 Catalytic Hydrogenation

Reaction showing Catalytic Hydrogenation

This method is usually not known as effective or selective as the use of hydride reagents.

5.4.2 Reduction with Metal Hydrides

1. Primary alcohol is produced on reduction of an aldehyde.

Example:

Reaction showing Catalytic Hydrogenation

2. Secondary alcohol is produced on reduction of a ketone.

Example:

Reaction showing reduction of a ketone to form a Secondary alcohol.

3. Tertiary alcohol is produced on reduction of an acid or ester.

Example:

Reaction showing reduction of an acid or ester to form a Tertiary alcohol .

Reduction of $LiAlH_4$ and $NaBH_4$

Reaction showing reduction of various functional groups in the presence of

6. Reaction of Alcohols

Flow chart showing reactions of alcohols

6.1 Dehydration 

Dehydration Reaction of alcohol

6.2 Substitution

Substitution  Reaction of alcohol

6.3 Esterification 

It is catalyzed by an acid or a base.

Esterification Reaction of alcohol

6.4 Tosylation

It is used to convert poor leaving group OH to good leaving group OTs.

Example:

Tosylation Reaction of alcohol

6.5 Oxidation 

1. Primary Alcohols

Oxidation Reaction of  primary alcohol

2. Secondary alcohols

Oxidation Reaction of Secondary alcohol

In the presence of any oxidizing agent, secondary alcohol is oxidized to alcohol.

3. Tertiary alcohols

Oxidation Reaction of tertiary alcohol

$\mathrm{MNO}{_2}$ is an oxidizing agent which is used to oxidise only benzylic, allylic and propargylic alcohols.

Showing benzylic, allylic and propargylic alcohols.

Common Phenols and Aromatic Ethers

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7. Preparation of Phenols

Flow chart showing various methods of preparation of phenol

7.1 Dow’s Process

It is an industrial method which is used for the preparation of phenol. It takes place through a benzene mechanism.

Example: 

Showing Dow’s Process

7.2 Cumene Process

Example:

Showing Cumene Process

7.3 Distillation of phenolic acids with soda lime

Example: 

7.4 Benzene

Example: 

Showing reaction of Benzene with Hydrogen peroxide to yield phenol

7.5 Grignard Reagent

Example: 

Showing the formation of phenol using grignard reagent

8. Reaction of Phenols

8.1 Formation of Ethers

1. Williamson Synthesis

Showing the Reaction of phenols - Williamson synthesis

2. Nucleophilic Aromatic Substitution

Example:

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8.2 Formation of Esters

Example: 

Showing the Reaction of phenols - Formation of Esters

8.3 Fries Rearrangement

Example:

Showing the Reaction of phenols - Fries Rearrangement

8.4 Reactions of Benzene Ring

8.4.1 Hydrogenation

Example:

Showing the Reaction of phenols - Hydrogenation

8.4.2 Oxidation to Quinones

Example:

Showing the Reaction of phenols - Oxidation to quinones

8.4.3 Electrophilic Substitution

1. Halogenation

Example:

Showing the Reaction of phenols - Electrophilic substitution (a) Halogenation

2. Nitration

Showing the Reaction of phenols - Electrophilic substitution (b) Nitration

3. Sulphonation

Showing the Reaction of phenols - Electrophilic substitution (c) Sulphonation

4. Diazonium Salt Coupling-Azophenols

\[{\text{Ar}}{{\text{N}}_{\text{2}}}^ \oplus  + {{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{G}} \to {\text{p}} - {\text{G}} - {{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}} - {\text{N}} = {\text{N - Ar}}\] 

Here, G is an electron releasing groups such as -OH, -OR.

5. Ring Alkylation

Example:

Showing the Reaction of phenols - Electrophilic substitution (e) Ring Alkylation

RX and $\text{AlC}{{\text{l}}_{3}}$ give poor yields as aluminum chloride coordinates with lone pairs of oxygen. 

6. Kolbe’s Synthesis

Example:

Showing the Reaction of phenols - Electrophilic substitution (f) Kolbe’s Synthesis

7. Reimer-Tiemann Synthesis of phenolic Aldehydes 

Example:

Showing the Reaction of phenols - Electrophilic substitution (g) Reimer-Tiemann Synthesis of phenolic Aldehydes

This reaction involves the formation of $\text{CC}{{\text{l}}_{2}}$. 

8. Formation of Aspirin

Example:

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9. Formation of oil of wintergreen

Example:

Showing the Reaction of phenols - Electrophilic substitution (j) Formation of oil of wintergreen

9. Ethers

9.1 Williamson Ether Synthesis

 \[{\text{R}} - {{\text{O}}^ - } + {\text{R}}' - {\text{X}} \to {\text{R}} - {\text{O}} - {\text{R}}' + {{\text{X}}^ - }\] 

Note: 

Substrate and leaving Group in Williamson synthesis

1. Leaving group, that, is,  \[{\text{X}} = {\text{Cl, Br, I, OTs etc}}{\text{.}}\] 

2. Substrate-Alkyl group R’ should be primary. 

9.2 Alkoxymercuration-Demercuration

Showing the Alkoxymercuration-Demercuration

This type of reaction follows Markovnikov orientation.

9.3 Bimolecular Dehydration of Alcohols 

This is an industrial method which is used for the synthesis of ethers.

\[2\text{R}\frac{{{\text{H}}^{\oplus }}}{{{1}^{{}^\circ }}}\text{OH}\overset{{}}{\mathop{\text{R}}}\,-\text{O}-\text{R}+{{\text{H}}_{2}}\text{O}\] 

10. Reactions of Ethers

10.1 Cleavage by HBr and HI

Showing the Cleavage by HBr and HI

10.2 Autoxidation 

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11. Preparation of Epoxide

11.1 Peroxy Acid Epoxidation

Showing the Preparation of epoxide-1 Peroxy Acid Epoxidation

11.2 Base-Promoted Cyclization of Halohydrins 

Showing the Preparation of epoxide-2 Base-promoted cyclization of halohydrins

Example

Showing the reaction of 2-Chloro-1-Phenylethanol tp yield 2-Phenyloxirane

12. Reactions of Epoxides 

12.1 Acid-Catalyzed Opening

1. In Water

Showing the Reactions of Epoxides - (a) In water

Anti-stereochemistry is followed here.

2. In Alcohols

Showing the Reactions of Epoxides - (b) In alcohols

Here, the alkoxy group is bonded to the more highly substituted carbon.

Example:

Reaction of methyl Oxirane to yield 2-Methoxy-propan-1-ol

3. Hydrohalic Acids (X = Cl, Br, I)

Showing the Reactions of Epoxides - (c) Hydrohalic Acids (X = Cl, Br, I)

12.2 Base-Catalyzed Opening

1. With Alkoxides

Showing the Reactions of Epoxides - 2 Base-Catalyzed opening (a) With Alkoxides

The alkoxy group is bonded to less highly substituted carbon.

Example:

Reaction of Propylene oxide to yield 1-Methoxy-2-propanol

2. With Organometallics

Showing the Reactions of Epoxides - 2 Base-Catalyzed opening (b) With Organometallics

Example:

Reaction of Propylene oxide to yield 1-Cyclohexyl-2-Propanol

Note:

Opening of Epoxide Ring

1. In acid catalyzed opening, a nucleophile attacks the epoxide carbon, allowing a more stable carbocation to be formed.

2. Nucleophile attacks on the less hindered carbon in base catalyzed opening.

13. Acidic Strength 

1. Despite the fact that oxygen is more electronegative than sulfur, alcohols are weaker acids than thiols. $\text{R}{{\text{O}}^{-}}$, the conjugate base of alcohol, is more basic than $\text{R}{{\text{S}}^{-}}$ because the negative charge in $\text{R}{{\text{O}}^{-}}$ is placed on smaller oxygen atoms, resulting in higher charge density. However, because the $\text{R}{{\text{S}}^{-}}$ negative charge is dispersed on larger sulphur, it is a poor base and its conjugate acid is more acidic.

2. Due to the +I effect of the alkyl group, all alcohols (except $\mathrm{CH}_{3} \mathrm{OH}$) are weaker than $\mathrm{H}_{2} \mathrm{O}$. $\mathrm{CH}_{3} \mathrm{OH}$ is slightly more powerful than $\mathrm{H}_{2} \mathrm{O}$. Because of the electron withdrawing benzene ring and the resonance stabilized phenolic ion, phenols are stronger than alcohol. Because alkoxide ions, the conjugate base of alcohol, lack resonance, they are less stable and more basic. Phenol is less stable than carboxylic acid, which has a strong electron-drawing carbonyl group and more stable, resonating structures.

14. Test for Alcohols, Phenols and Ethers

14.1 Analysis of Alcohols-Characterization

1. Cold concentrated sulfuric acid dissolves alcohols. This property is shared by alkenes, amines, almost all oxygen-containing compounds, and easily sulfonated compounds. (Alcohol, like other oxygen-containing compounds, produces oxonium salts that dissolve in the highly polar sulfuric acid.)

2. Cold dilute, neutral permanganate does not oxidize alcohols (although primary and secondary alcohols are oxidized by permanganate under more vigorous conditions). However, as we've seen, alcohols frequently contain impurities that oxidize under these conditions, so the permanganate test should be used with caution.

3. Alcohols have no effect on the color of bromine in carbon tetrachloride. This characteristic distinguishes them from alkenes and alkynes.

4. The evolution of hydrogen gas from alcohol reactions with sodium metal is useful in characterization.

5. The formation of an ester upon treatment with an acid chloride or anhydride often indicates the presence of a hydroxide group in a molecule. Some esters have a pleasant odor; others have high melting points and can be used to make identifications. 

6. The Lucas test, which is based on the difference in reactivity of the three classes towards hydrogen halides, determines whether an alcohol is primary, secondary, or tertiary. Alcohols with fewer than six carbons are soluble in the Lucas reagent, which is a solution of concentrated hydrochloric acid and zinc chloride. The cloudiness that appears when the chloride separates from the solution indicates the formation of a chloride from an alcohol. As a result, the time required for cloudiness to appear is a measure of the alcohol's reactivity. The Lucas reagent reacts immediately with tertiary alcohol. Within five minutes, a secondary alcohol reacts. At room temperature, a primary alcohol does not react significantly. Benzyl alcohol and alllyl alcohol react with the Lucas reagent as quickly as tertiary alcohols. Allyl chlorides, on the other hand, is soluble in the reagent.

Showing which alcohol gives positive or negative Iodoform test.

Oxidation, halogenation, and cleavage are all involved in the reaction.

Showing Oxidation, halogenation, and cleavage reactions.

14.2 Analysis of Glycols, Periodic Acid Oxidation

$\mathrm{HI}{O_4}$ compounds with two or more-OH or C=O groups attached to adjacent carbon atoms undergo oxidation with cleavage of carbon-carbon bonds when exposed to periodic acid.

Showing Analysis of Glycols, Periodic Acid Oxidation

14.3 Miscellaneous Tests

1. Ceric Ammonium Nitrate Test- 

With this reagent, alcohols produce a red color.

 \[{\text{Ce}}{\left( {{\text{N}}{{\text{H}}_{\text{4}}}} \right)_{\text{2}}}{\left( {{\text{N}}{{\text{O}}_{\text{3}}}} \right)_{\text{6}}}{\text{  +  RC}}{{\text{H}}_{\text{2}}}{\text{OH}} \to {\text{Ce}}{\left( {{\text{N}}{{\text{H}}_{\text{4}}}} \right)_{\text{2}}}{\left( {{\text{N}}{{\text{O}}_{\text{3}}}} \right)_{\text{5}}} + {\text{RCOOH + HN}}{{\text{O}}_{\text{3}}}\] 

2. Potassium Dichromate Test – 

Alcohols change the color of orange dichromate to green. Tertiary alcohols fail this test.

3. Ester test:

Alcohol produces a fruity aroma of ester with carboxylic acid.

4. Methanol reacts with salicylic acid to produce winter green oil.

14.4 Victor Meyer's Test

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14.5 Differentiation Test

14.5.1 Alcohols and Phenols

1. Litmus Test: Phenol turns blue litmus red but not alcohol.

2. Ferric Chloride: 

$\mathrm{FeCl}_{3}: \text { Phenol } \stackrel{\text { Neutral } \mathrm{FeCl}_{3}}{\longrightarrow} \text { Blue-Violet }$ 

3. Coupling Reaction:

$\text { Phenol + Diazonium Salt } \frac{\text { weakly basic }}{\text { medium }} \text { Yellow or }$

$\text { Diazonium Salt + Alcohol } \frac{\text { weakly basic }}{\text { medium }} \text { No Reaction }$

4. Bromine Water Test:

Showing Bromine Water test

14.4.2 Alcohols and Ethers

1. Alcohols react with Na to give ${{\text{H}}_{2}}$, but not ethers.

2. Alcohol gives fumes of HCl with ${{\text{PCl}}_{5}}$ but not ethers.

14.5.3 Sodium Bicarbonate Test

Phenol, ROH and $\mathrm{H}_{2} \mathrm{O}$ do not displace $\mathrm{CO}_{2}$ from carbonate \& bicarbonates but $\mathrm{RCOOH} \& \mathrm{RSO}_{3} \mathrm{H}$ gives brisk effervescence of $\mathrm{CO}_{2}$ which proves that $\mathrm{RCOOH} \& \mathrm{RSO}_{3} \mathrm{H}$ are stronger acids $\mathrm{H}_{2} \mathrm{CO}_{3}$ but phenol is weaker acid than $\mathrm{H}_{2} \mathrm{CO}_{3}$. Nitrophenols also give effervescence of $\mathrm{CO}_{2}$ with $\mathrm{Na}_{2} \mathrm{CO}_{3}$. Trinitrophenol (Picric Acid) is highly acidic due to strong electron withdrawing effect of three groups its acidic strength is comparable to that of carboxylic acids. Its anion is highly resonance stabilised.

$\mathrm{RCOOH}+\mathrm{NaHCO}_{3} \longrightarrow \mathrm{RCOON}^{\ominus \oplus}+\mathrm{CO}_{2} \uparrow+\mathrm{H}_{2} \mathrm{O}$

$\mathrm{Ph}-\mathrm{OH}+\mathrm{NaHCO}_{3} \longrightarrow \text { No Reaction}$

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15.5.4 $\mathrm{FeCl}_{3}$ Test:

Phenol gives characteristic purple colour with $\mathrm{FeCl}_{3}$ but alcohols do not react with $\mathrm{FeCl}_{3}$. Carboxylic acids also form buff coloured precipitate with $\mathrm{FeCl}_{3} .$ Only acetic acid forms red coloured precipitate with $\mathrm{FeCl}_{3}$, so it can be used as a test for acetate salts.

Showing Ferric Chloride Test in case of phenols

Class 12 Chemistry Chapter 7 Important Topics and Subtopics Covered 

Class 12 Chemistry Chapters 7 Details, Formulas and Concepts

1. Nomenclature: Understanding the IUPAC nomenclature rules for alcohols, phenols, and ethers is crucial. For example:

• Alcohols: Named by replacing the -e suffix of the corresponding alkane with -ol.

• Phenols: Named by adding the suffix -ol to the name of the parent aromatic hydrocarbon.

• Ethers: Named by naming the alkyl groups attached to oxygen in alphabetical order followed by the word ether.

2. Preparation Methods: There are various methods for the preparation of alcohols, phenols, and ethers. Some important ones include:

• Alcohol: From Alkene (Hydration), From Grignard reagent, From Alkyl Halides (Substitution), etc.

• Phenols: From Benzene sulfonic acid, From diazonium salts, etc.

• Ethers: Williamson synthesis, Dehydration of alcohols, etc.

3. Reactions of Alcohols: Alcohols undergo various reactions such as:

• Oxidation: Alcohols can be oxidized to corresponding aldehydes, ketones, or carboxylic acids depending on the oxidizing agent and conditions.

• Esterification: Reaction with carboxylic acids to form esters in the presence of an acid catalyst.

• Dehydration: Elimination of water to form alkenes in the presence of a strong acid catalyst.

4. Reactions of Phenols: Phenols exhibit acidic properties due to the presence of the -OH group attached to the aromatic ring. Important reactions include:

• Reaction with metals to form phenoxide ions.

• Reaction with alkalis to form salts.

• Esterification to form esters.

5. Williamson Ether Synthesis: This method is used for the preparation of ethers by the reaction of alkyl halides with sodium or potassium alkoxide. The general reaction is: R-X+RO→ R-O-R + X¯

Importance of Revision Notes for Class 12 Chemistry Chapter 7

• Summarises Key Points: Condenses important concepts for quick review.

• Saves Time: Provides a fast way to revise before exams.

• Highlights Essentials: Focuses on crucial topics and definitions.

• Improves Memory: Helps in better retention of information.   

• Enhances Exam Prep: Targets weak areas for more effective study.

• Clarifies Concepts: Simplifies complex ideas for easier understanding.

• Includes Visuals: Uses diagrams and charts for better grasp.

• Boosts Confidence: Prepares students thoroughly for exams.

Tips For Learning the Class 12 Chapter 7 

1. Focus on core processes with illustrations and examples.

2. Draw and label diagrams for clarity. 

3. Create summaries of each process.

4. Connect concepts to everyday examples.

5. Solve past exam questions to test understanding.

6. Explain concepts to others to reinforce learning.

7. Revisit material frequently to retain information.

Conclusion

Chapter 7 Alcohols, Phenols, and Ethers provides a detailed understanding of these organic compounds, their structures, properties, and reactions. By learning about their various uses in industrial and biological contexts, students gain insight into their significance in the real world. Mastering the concepts in this chapter helps students not only in exams but also in understanding the foundational aspects of organic chemistry.

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