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Free NCERT Class 12 Chemistry Chapter 11 Notes Alcohols, Phenols and Ethers - Download PDF

Free NCERT Class 12 Chemistry Chapter 11 Notes Alcohols, Phenols and Ethers - Download PDF

Edited By Shivani Poonia | Updated on Jul 08, 2025 06:10 PM IST

Do you know that over 100 billion litres of ethanol is produced every year globally, or the first antiseptic used in surgery was Phenol? All these interesting facts are discussed in Alcohols, Phenols, and Ethers which are important classes of compounds that feature oxygen-containing organic compounds. When the OH group replaces the hydrogen atom in aliphatic hydrocarbons, Alcohols are formed same goes for phenols when the OH group replaces the hydrogen of aromatic hydrocarbons, then Phenols are formed while Ethers are formed when the alkoxy (R-O) or aryloxy (Ar-O) group substitutes the hydrogen atom in hydrocarbons.

This Story also Contains
  1. NCERT Notes for Class 12 Chapter 7: Download PDF
  2. NCERT Notes for Class 12 Chapter 7
  3. Alcohols ,Phenols and Ethers Previous Year Question and Answer
  4. CBSE Class 12 NCERT Chemistry Chapter-Wise Notes
  5. Subject-Wise NCERT Solutions
  6. Subject-Wise NCERT Exemplar Solutions
Free NCERT Class 12 Chemistry Chapter 11 Notes Alcohols, Phenols and Ethers - Download PDF
Free NCERT Class 12 Chemistry Chapter 11 Notes Alcohols, Phenols and Ethers - Download PDF

NCERT Class 12 Chemistry notes of Chapter 7 provide a structured approach to understanding the classification, properties, preparation, and reactions. NCERT Notes are prepared by our subject experts in a comprehensive way that helps students understand the concepts in a very simple and easy way. These notes cover all the topics as prescribed by the latest CBSE syllabus, and selected previous year questions are also added to help enhance the clarity and problem-solving ability of students.

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NCERT Notes for Class 12 Chapter 7: Download PDF

These concise NCERT notes cover all the key concepts of alcohol, phenol and ethers to help students in quick revision before the exam. You can download the NCERT notes PDF from the button given below

Download PDF

NCERT Notes for Class 12 Chapter 7

Alcohols, Phenols and Ethers notes are given below and they covers all concepts of the NCERT textbook and explains them in a concise and easy-to-understand manner. Whether revising or studying for the first time these NCERT notes are a boon for students who aim to score well in their exams.

Classification

The classification of compounds Alcohold, Phenols and Ethers makes their study systematic and hence simpler.

1. Alcohols Mono, Di, Tri or Polyhydric alcohols

Alcohols and phenols are classed as monohydric, dihydric, trihydric, or polyhydric depending on how many hydroxyl groups they have in their molecules.

According to the hybirdisation of Carbon atom to which the hydroxyl group is attached, Monohydric alcohols are further classified:

(i). Compounds containing Csp3OH group: Alcohols in which the –OH group is attached to an sp3 hybridised carbon atom of an alkyl group.

They are further classified as:

(a). Primary, secondary and tertiary alcohols: The –OH group is attached to primary, secondary and tertiary carbon atom.

Primary alcohol

Secondary alcohol

Tertiary alcohol

Primary Secondary Tertiary

(b). Allylic alcohols: The OH group is attached to a sp3 hybridised carbon adjacent to the carbon-carbon double bond, that is to an allylic carbon.

(c). Benzylic alcohols: The OH group is attached to a sp3 hybridised carbon atom next to an aromatic ring.

(ii) Compounds containing Csp2OH bond

These alcohols contain OH group bonded to a carbon-carbon double bond, i.e., to a vinylic carbon or to an aryl carbon. These alcohols are also known as vinylic alcohols.

Vinylic alcohol: CH2=CHOH

2. Phenols Mono, Di and trihydric phenols

3. Ethers

Ethers are classified as simple or symmetrical, if the alkyl or aryl groups attached to the oxygen atom are the same, and mixed or unsymmetrical, if the two groups are different.

Nomenclature

1. Alcohols

The common name of an alcohol is derived from the common name of the alkyl group and adding the word alcohol to it. For example, CH3OH is methyl alcohol.

IUPAC Nomenclature:

  • Select the longest chain containing the OH group.
  • Number the carbon so that the OH group gets the lowest possible position

  • Remove e from the alkane name and add ol.

  • Mention the position of the OH group

2. Phenols

The simplest hydroxy derivative of benzene is phenol. It is its common name and also an accepted IUPAC name.

IUPAC Nomenclature

  • The parent compound is phenol.
  • Number the ring in such a way so that the substituents gets the lowest possible position.
  • Name and prefix substituents with their positions.

3. Ethers

Common names of ethers are derived from the names of alkyl/ aryl groups written as separate words in alphabetical order and adding the word ‘ether’ at the end.

IUPAC Nomenclature

  • Name the longerst alkyl group as the base.
  • Name the shorter alkyl group as an alkoxy group.
  • Combine them as alkoxyalkane.

Structure of Functional Groups

Alcohols have sp3 hybridized oxygen atoms and hybrid atomic orbitals in a tetrahedral configuration. The R group determines the value of the ROH bond angle. Due to lone pair repulsion, this angle for methyl alcohol is (C – O – H) 108.9°.The -OH group in phenols is connected to sp2 hybridized carbon, giving the C – O bond a partial double bond nature.

Alcohols and Phenols

Preparation of Alcohols

Alcohols are prepared by the following methods:

1. From alkenes

(i). By acid catalysed hydration

This reaction is in accordance with Markonikov's rule,

CH3CH=CH2 + H2O → CH3-CH(OH) - CH3

Mechanism

It involves 3 steps:

Step1. Protonation of alkene to form carbocation by electrophilic attack of H3O+

H2O+H+H3O+

Step 2. Nucleophilic attack of water on carbocation

Step 3: Deprotonation to form an alcohol

(ii). By hydroboration-oxidation

By hydroboration-oxidation of alkenes, alcohols can be prepared, where BH3 adds across the double bond followed by oxidation with H2O2/NaOH to give alcohols with anti-Markovnikov orientation.

1648026447797

2. From carbonyl compounds

(i). By reduction of aldehydes and ketones

RCHO + H2 → RCH2OH

RCORNaBH4RCH(OH)R

(ii). By reduction of carboxylic acids

RCOOH LiAl 4,H2OROH

3. From Grignard reagents

All three types of monohydric alcohols can be prepared by the use of Grignard reagents. Grignard reagents form addition compounds by nucleophile attack with aldehydes and ketones which on hydrolysis with dilute acid yields alcohol.

HCHO+RMgXH2ORCH2OH+Mg(OH)X

RCHO+RMgXH2ORCH(R)OH+Mg(OH)X

RCOR+RMgXH2ORC(R)(R)OH+Mg(OH)X

Preparation of Phenols

Phenol, also known as carbolic acid, and is commercially produced synthetically. In the laboratory, phenols are prepared from benzene derivatives by any of the following methods:

1). From haloarenes

Chlorobenzene is fused with NaOH at 623K and 320 atmospheric pressure. Phenol is obtained by acidification of sodium phenoxide so produced. The reaction occurs as follows.

1648026443653

2). From benzenesulfonic acid

Benzene is sulphonated with oleum and benzene sulphonic acid so formed is converted to sodium phenoxide on heating with molten sodium hydroxide. Acidification of the sodium salt gives phenol. The reaction occurs as follows:

1648026442864

3). From diazonium salts

A diazonium salt is formed by treating an aromatic primary amine with nitrous acid (NaNO2 + HCl) at 273-278 K. Diazonium salts are hydrolysed to phenols by warming with water or by treating with dilute acids. The reaction occurs as follows.

1648026443304

4). From Cumenes

Phenol is manufactured from the hydrocarbon, cumene. Cumene (isopropylbenzene) is oxidised in the presence of air to cumene hydroperoxide. It is converted to phenol and acetone by treating it with dilute acid. Acetone, a by-product of this reaction, is also obtained in large quantities by this method. The reaction occurs as follows:

1648026448242

Physical Properties

Alcohols and phenols consist of two parts, an alkyl/aryl group and a hydroxyl group. The properties of alcohols and phenols are chiefly due to the hydroxyl group. The nature of alkyl and aryl groups simply modify these properties:

(i). Boiling points of alcohols and phenols rise with increasing carbon atoms due to stronger van der Waals forces, but decrease with branching due to reduced surface area. They have higher boiling points than hydrocarbons, ethers, haloalkanes, and haloarenes of similar masses, mainly because of intermolecular hydrogen bonding. For example, despite similar molecular masses, ethanol boils much higher than propane, while methoxymethane shows an intermediate boiling point, reflecting the absence of hydrogen bonding in ethers.

(ii). Lower alcohols are colourless liquids, C5–C11 alcohols are oily liquids, and C12 and higher alcohols are waxy solids. Alcohols are miscible with water because their hydroxyl groups can form H-bonds with water. With increasing molecular mass, solubility decreases. Because polar molecules have intermolecular hydrogen bonding, the boiling points of alkanes are greater than expected.

(iii). These are colourless liquids or crystalline solids that turn coloured over time due to gradual oxidation in the presence of air. Carboxylic acid is another name for phenol. Phenols establish intermolecular H-bonds with other phenol molecules and with water due to the presence of a polar -OH bond.

(iv). Alcohols and phenols are soluble in water due to hydrogen bonding with water molecules. However, solubility decreases as the size of the hydrophobic alkyl or aryl group increases. Lower molecular mass alcohols are completely miscible with water.

Chemical Reactions

Alcohols react both as nucleophiles and electrophiles. The bond between O–H is broken when alcohols react as nucleophiles. They are versatile compounds.

Alcohols as Nucleophiles

Alcohols as electrophiles

1). Reactions involving cleavage of O–H bond

Reactions involving cleavage of the O–H bond in alcohols and phenols typically involve the release of a proton, showcasing their acidic nature. These reactions often form alkoxides or phenoxides when treated with active metals or strong bases.

i). Acidity of alcohols and phenols

a). Reaction with metals

2ROH+2Na yields 2RONa+H2

1648026444880

b). Acidity of alcohols

The acidic character of alcohols arises from the polar O–H bond. Electron-releasing groups increase electron density on the oxygen atom, reducing the O–H bond polarity and thus decreasing the acidity.

Alcohols are weaker acids than water.

b). Acidity of phenols

Because the phenoxide ion is stabilized through resonance, phenol is more acidic than alcohols. The presence of an electron withdrawing group raises phenol's acidity by stabilizing the phenoxide ion, whereas the presence of an electron releasing group lowers phenol's acidity by destabilizing the phenoxide ion. sp2-hybridised carbon of the benzene ring directly bonded to the hydroxyl group is more electronegative than the oxygen itself, withdrawing electron density from the –OH group. This increases the polarity of the O–H bond, promoting ionisation and formation of the phenoxide ion.

(ii). Esterification

Reaction of Alcohols and phenols with carboxylic acids, acid chlorides and acid anhydrides form esters.

Ar/ROH+RCOOHH+Ar/ROCOR+H2O

Ar/R-OH + (RCO,)2O + H+↔ Ar/ROCOR, + RCOOH

R/ArOH + R,COCl Pyridine→ R/ArOCOR, + HCl

2). Reactions involving cleavage of carbon oxygen (C–O) bond in alcohols

Reactions involving cleavage of the C–O bond in alcohols typically occur during substitution or elimination, where the hydroxyl group is replaced or removed forming alkyl halides or alkenes.

i). Reaction with hydrogen halides

ROH + HX yields→ RX + H2O

ii). Reaction with phosphorus trihalides:

3ROH+PBr33RBr+H3PO3

iii). Dehydration

Alcohols undergo dehydration means removal of a molecule of water to form alkenes on treating with a protic acid.

Order of reaction

Tertiary > Secondary > Primary

Mechanism of dehydration

Step 1: Formation of protonated alcohol

Step 2: Formation of carbocation

Step 3: Formation of ethene by elimination of a proton.

iv). Oxidation

Formation of a carbon oxygen double bond with cleavage of an O-H and C-H bonds is involved in oxidation of alcohol.

Alcohol, Acidified KMnO4→ Carboxylic acid

RCH2OH Oxidation→ RCHO yields→ RCOOH

3). Reactions of phenol

Phenol undergoes characteristic reactions. Its aromatic ring is highly reactive due to the activating effect of the –OH group.

i). Electrophilic aromatic substitution

Electrophilic substitution reactions take place on aromatic ring in phenols. The OH group attached to the benzene ring activates it towards electrophilic substitution. Also, it directs the incoming group to ortho and para positions in the ring as these positions become electron rich due to the resonance effect caused by OH group.

a). Halogenation

Anisole reacts with an alkyl halide and acyl halide introducing alkyl and acyl groups in ortho and para positions.

1648026446584

1648026444200

b). Nitration

With dilute nitric acid at low temperature (298 K), phenol yields a mixture of ortho and para nitrophenols. The reaction occurs as follows.

1648026448715

ii). Reimer-Tiemann reaction

Phenols for aromatic compounds containing EDG when refluxed with CHCl3 and alkali yield o- and p- hydroxybenzaldehyde. The ortho product is the predominant product. It is an electrophilic substitution on PhO- ion. The electrophile is dichlorocarbene (:CCl2) which contains a C with only six electrons.

1648026445581

iii). Kolbe’s reaction

Phenol when heated at(390-410K) under pressure with CO2 and alkali gives salicylic acid after acidification in addition to some amount of p-isomer.

1648026445920

iv). Reaction of phenol with zinc dust

When phenol is distilled with zinc dust, benzene is obtained. The reaction occurs as follows:

v). Oxidation

1648026446222

Some Commercially Important Alcohols

Two commercially important alchols are Methanol and ethanol.

Methanol (CH3OH)

Wood-spirit is another name for it. It is a clear liquid with no discernible colour. It reaches a temperature of 337 degrees Fahrenheit when it boils. It is extremely poisonous. Even little doses can cause blindness, and excessive doses can be very fatal.

Paints, varnishes, and other products use it as a solvent.It can be used to make formaldehyde.

Ethanol (C2H5OH)

It is known as denatured spirit when combined with CuSO4 and pyridine.It is a colourless liquid having boiling point 351 K.

C12H22O11+H2O Invertase C6H12O6+C6H12O6

C6H12O6 Zymase 2C2H5OH+2CO2

It is a good solvent, Sterilization of surgical tools in laboratories and hospitals.

Ethers

Ethers are organic compounds in which two alkyl or aryl groups are bonded to the same oxygen atom.

Preparation of Ether

1). By dehydration of alcohols

Alcohols lose water in the presence of protic acids like H2SO4 or H2PO4. The product formed alkene or ether depends on temperature. For instance, ethanol gives ethene at 443 K, while at 413 K, it mainly forms ethoxyethane.

CH3CH2OH443 KH2SO4CH2=CH2

CH3CH2OH 413 KH2SO4C2H5OC2H5

2). Williamson synthesis

It is the best method to prepare all type of ethers, that is, simple, mixed or aromatic ethers. Here, alkyl halides are treated with sodium alkoxide in presence of magnesium to give ethers. It involves SN2 mechanism during the attack of R-O- on R-X, that is, backside attack occurs here. The reaction occurs as follows:

Some examples include:

Physical Properties of Ethers

Since ethers' C-O bonds are polar, they have a net dipole moment. Their boiling points are equivalent to alkanes with similar molecular weights, although they are lower than alcohols. It's because ethers don't have H-bonding. Ether miscibility with water is similar to that of alcohols of same molar mass. It's because ethers, like alcohols, can make H-bonds with water.

Chemical Reactions

Ethers are generally unreactive but undergo cleavage with strong acids like HI or HBr, forming alcohols and alkyl halides.

1). Cleavage of C–O bond in ethers

The cleavage of C-O bond in ethers takes place under drastic conditions with excess of hydrogen halides. The reaction of dialkyl ether gives two alkyl halide molecules

R-O-R + HX → RX + R-OH

R-OH + HX → R-X + H2O

1648026444555

2). Electrophilic substitution reactions

The alkoxy group is ortho, para directing and activates the aromatic ring towards electrophilic substitution in the same way as in phenol.

i). Halogenation

1648026445212

ii). Friedel craft’s reaction

Anisole reacts with an alkyl halide and acyl halide introducing alkyl and acyl groups in ortho and para positions.

1648026449099

iii). Nitration

Anisole reacts with a mixture of concentrated sulphuric and nitric acids to yield a mixture of ortho and para nitroanisole. The reaction occurs as follows.

1648026446904

Alcohols ,Phenols and Ethers Previous Year Question and Answer

Slected questions from previous year exams are given below:

Question 1: Which of the following are benzylic alcohols?

(1) (i) and (ii)

(2) (iii) and (iv)

(3) (ii) and (iii)

(4) (ii) and (iv)

Answer:

The answer is the option (ii) and (iii).

The most prominent way to identify benzylic alcohol is to check if an -OH group is attached to a sp3 hybridised carbon atom on an aromatic ring.

As in the case of option (ii) and (iii), the sp3 hybridised carbon is attached to a benzene ring these are benzylic alcohols but in option (i) and (iv), the sp3 hybridised carbon is not attached to a benzene ring.

Hence, the answer is the option (3).

Question: Phenol can be distinguished from ethanol by the reactions with _________.

(i) Br2/ water

(ii) Na

(iii) Neutral FeCl3

(iv) All the above

(1) (i) and (iii)

(2) (iii) and (iv)

(3) (ii) and (iii)

(4) None of above

Answer:

The answer is the option (i) and (iii).

Phenol can easily be distinguished from ethanol by adding bromine water as it results in a white ppt of tri-bromo phenol or Neutral FeCl3 can also be used for this purpose. But ethanol being aliphatic alcohol will not react with either of the compounds.

Hence, the answer is the option (1). Question:

Question: Which of the following reactions will yield phenol?

(1) (A), (B) and (C)

(2) (A), (B) and (D)

(3) (A), (C) and (D)

(4) (B), (C) and (D)

Answer:

The answer is the option (A), (B), (C). To carry out these reactions, the conditions required should be easy to maintain. The reaction occurring in (D) is a nucleophilic substitution of chlorobenzene which is not feasible as it requires drastic temperature and pressure conditions.

The reaction given in (A) is the Dow process, (B) is aniline diazotisation and (C) option contains a reaction from benzene sulphonic acid. All these reactions are feasible due to manageable reaction conditions.

Hence, the answer is the option (1).

CBSE Class 12 NCERT Chemistry Chapter-Wise Notes

The link of the NCERT Class 12 chemistry chapter-wise notes is given below:

Subject-Wise NCERT Solutions

Subject-wise links of ncert solutions are given below:

Subject-Wise NCERT Exemplar Solutions

Subject-wise links of ncert exemplar solutions are given below:

NCERT Books and Syllabus

The links below will give you access to books and a syllabus for Class 12

Frequently Asked Questions (FAQs)

1. What are alcohols and how are they classified?

Alcohols are organic compounds that contain one or more hydroxyl groups attached to a carbon atom. They are classified based on the number of carbon atoms connected to the -OH bearing carbon:

primary (1°), secondary (2°), or tertiary (3°) alcohols.  

2. What is the difference between alcohols and phenols?

Both alcohols and phenols contain hydroxyl groups, the key difference lies in the structure. Alcohols have the -OH group attached to an aliphatic carbon atom , whereas phenols have the -OH group attached to a carbon in an aromatic ring.  

3. What are the common uses of alcohols?

Alcohols have diverse applications, including as solvents, in the production of pharmaceuticals, and as fuels. Ethanol is used in alcoholic beverages, as an industrial solvent, and as a biofuel.  

4. What are some common reactions of alcohols?

Alcohols can undergo several key reactions, including dehydration to form alkenes, oxidation to produce aldehydes or ketones, and esterification where alcohol reacts with acids to form esters.  

5. Why are ethers considered relatively unreactive compared to alcohols and phenols?

Ethers are generally less reactive due to the stable nature of the C-O-C bond. They do not readily participate in reactions like alcohols and phenols because they lack a hydroxyl group, which is reactive and can donate protons.  

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A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

Option 2)

\; K\;

Option 3)

zero\;

Option 4)

K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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