Alcohols are substances that have a hydroxyl group (-OH) linked to a saturated carbon atom. Alcohol is a carbon-containing chemical molecule with a hydroxyl functional group attached. Alkenes, carbonyl compounds, alkyl halide hydrolysis, primary amines, alcohol fermentation, and ether hydrolysis are all sources of alcohol.
An aliphatic carbon’s hydrogen atom is replaced by a hydroxyl group in alcohols. As a result, there are two halves to an alcohol molecule. The first is alkylated, while the second is hydroxylated.
Alcohols are hydrocarbon derivatives with the -OH functional group, which means that a hydrogen atom has been substituted by -OH. There are three forms of alcohol: primary alcohol, secondary alcohol, and tertiary alcohol depending on the presence of hydroxyl groups in the chemical. -OH stands for the functional group of alcohol ( Hydroxyl group). Because the -OH group is connected to the carbon via a covalent connection, the nature of alcohol is predominantly covalent. Ethyl alcohol is also known as ethanol and is classified as a primary or one of the main alcohols. CnH2n + 1OH is the generic formula for alcohol.
Table of Contents
Chemical Reactions of Alcohol
Alcohol can behave as both a nucleophile and an electrophile in reactions involving alcohol. In reactions in which the link between O and H is broken, alcohols act as nucleophiles. In reactions when the connection between C and O is disrupted, alcohols can act as electrophiles.
Alcohol’s reaction with the metal: Sodium ethoxide and hydrogen gas are formed when ethanol interacts with sodium metal (a base).
Formation of Halides from Alcohols: The -OH group in alcohol is replaced by halogens such as chlorine or bromine.
R–OH + H–X ⇢ R–X + H–OH
where X can be any halogen atom-like Cl, Br, etc.
(CH3)3COH + HCl ⇢ (CH3)3CCl + H2O
Reaction of Alcohols with HNO3: In this process, there is oxidation as well as gas evolution (slow but steady).
R-OH + HO-NO2 → R-O-NO2
Dehydration of Alcohol: Primary alcohols undergo what reaction to generate alkenes, which is the most popular question asked by organic chemistry students. The dehydration reaction is the answer to this question. Alcohols are dehydrated to create alkenes when heated with a protonic acid such as conc. H2SO4 or H3PO4 at 443 K. In an acidic environment, alcohols dehydrate. According to Satyzeff’s Rule, intramolecular dehydration produces alkene, while intermolecular dehydration produces ether.
Hydrolysis of Alcohols: Alcohol hydrolysis is an oxidation reaction. Water serves as a catalyst in this reaction. The principal products of this hydrolysis process are aldehydes and ketones.
CH3CH2OH + H2O → CH3CHO + H2O + H2
Esterification of Alcohols: The creation of ester occurs when a carboxylic acid reacts with an alcohol and an acid catalyst (along with water). Fischer esterification is what it’s called. An acid or a base catalyzes esterification.
Haloform Reaction: In the presence of halogen and mild alkali, a chemical with the CH3CO- group (or a molecule that on oxidation gives the CH3CO – group) that is coupled with a C or H gives haloform. The haloform reaction will not affect CH3-CH2-COCH2-CH3, CH3-CO-Cl, or CH3COOH, however, the haloform reaction will affect CH3CH2OH.
Oxidation: The production of a carbon-oxygen double bond (C=O) with the breaking of O-H and C-H bonds occurs during the oxidation of alcohols. In oxidation reactions, this type of cleavage and bond creation takes place. Because dehydrogenation reactions include the loss of hydrogen from alcohol, they are also known as dehydrogenation reactions.
Primary Alcohol: A primary alcohol is easily oxidized to generate an aldehyde, which is followed by a carboxylic acid. The aldehyde and acid that result have the same number of carbon atoms as the parent alcohol.
Secondary Alcohol: With chromic anhydride, secondary alcohol can be quickly converted to a ketone. Under extreme conditions, the ketone might be further oxidized to produce an acid mixture. The ketone has the same amount of carbon atoms as the parent alcohol, but the acids produced have less. In the presence of an oxidizing agent, secondary alcohol is converted to the ketone.
Tertiary Alcohol: Because there is no hydrogen in the carbon-bearing hydroxyl group, tertiary alcohol is extremely difficult to oxidize (OH). When exposed to acidic oxidizing chemicals under very strong circumstances at very high temperatures, cleavage of various C-C bonds occurs, allowing for the oxidation of tertiary alcohol. They combine ketones with carboxylic acids to generate ketone-carboxylic acid combinations. The 4 number of carbon atoms in ketones and acids is lower than that of the beginning alcohols. MnO2 is an oxidizer that only oxidizes the alcohol allylic, benzylic, and propargylic.
Phenol
Ferdinand Runge, an 1834 scientist, discovered phenol. From coal tar, he was able to extract it. It’s a white, crystalline solid. Because phenol can cause chemical burns to the skin, it should be handled with caution. Phenolic acid is a different name for this substance. A six-membered aromatic ring immediately linked to a hydroxyl group is used to identify members of this species. The phenol family includes this species, which has the formula phenol. Now that you’ve learned s and the phenol formula, you’re ready to learn about the rest of the compound family.
An alkyl, alkynyl, cycloalkyl, or benzyl group could be the saturated carbon. Phenols, on the other hand, are chemicals that have a hydroxyl group connected to a benzene ring. Phenols are formed by cumene, diazonium salts, and other compounds.
Chemical Reactions of Phenol
Because a hydroxyl group linked to an aromatic ring acts as an ortho-para director, phenols are extremely reactive. As a result, phenol’s ortho and para carbons have a strong attraction for electrophilic aromatic substitution.
Williamson Synthesis: In laboratories, this is a crucial approach for making symmetrical and asymmetrical ethers. An alkyl halide reacts with sodium alkoxide to produce ether in the Williamson synthesis.
Nucleophilic Aromatic substitution
Formation of Ethers :
Fries Rearrangement:
Oxidation to Quinones: Despite the lack of a hydrogen atom on the hydroxyl-bearing carbon, phenols are relatively simple to oxidize. The dicarbonyl molecule para-benzoquinone (also known as 1,4-benzoquinone or simply quinone) is one of the colourful products of the oxidation of phenol by chromic acid. It also has an ortho isomer. Quinones are best synthesized from these chemicals, which can be easily reduced to their dihydroxy-benzene analogues. It’s worth noting that there are no meta-quinones with similar structures. Because the redox equilibria between the dihydroxy-benzenes hydroquinone and catechol and their quinone oxidation states are so simple, gentler oxidants such as chromate (Jones reagent) are frequently used.
Electrophilic Substitution: Ortho, para – directing is significantly activated by —OH and even —O(phenoxide). Because phenols are highly reactive and prefer both poly substitution and oxidation, electrophilic mono substitution occurs in unusually mild conditions.
Halogenation – Because the – OH group is highly reactive, phenol is commonly polysubstituted. To avoid poly substitution, the reaction should be carried out in a nonpolar solvent such as CS2 or CCl4 and at a low temperature. When phenols are treated with bromine in the presence of a low-polarity solvent such as CHCl3 at low temperatures, mono-bromophenol is formed. Even in the absence of Lewis acids, phenols are halogenated due to the hydroxyl group’s strong activating activity. Monobromophenols are generated when phenols are treated with bromine at low temperatures in the presence of a low-polarity solvent such as CHCl3. A white precipitate of 2, 4, 6-tribromophenol forms when phenol is treated with bromine water.
Nitrosation: When phenols are treated with weak nitric acid, they are nitrated at 298 K, yielding a combination of ortho and para nitrophenols. On the basis of their volatility, the resulting mixture is steam distilled into ortho and para nitrophenols. Ortho nitrophenols are less volatile than para nitrophenols because they have intramolecular and intermolecular hydrogen bonds, whereas para nitrophenols only have intermolecular hydrogen bonds.
Kolbe’s Synthesis: The phenoxide ion is generated when phenol is exposed to sodium hydroxide. This generated phenoxide ion is extremely reactive in electrophilic substitution processes. It performs an electrophilic substitution process when exposed to a weak electrophile (carbon dioxide), resulting in Ortho-hydroxybenzoic acid. Kolbe’s response is a common term for this reaction.
Riemer – Tiemann Synthesis of Phenolic Aldehydes: An aldehyde group forms at the ortho position of the benzene ring when phenol is treated with chloroform in the presence of sodium hydroxide. The Reimer-Tiemann response is what it’s called.
Ether
The ether group is an organic molecule that has an oxygen atom linked to two alkyl and aryl groups.
Ethers are organic compound types that contain an ether group, which is made up of an oxygen atom linked to two aryl or alkyl groups. R – O – R′ is the general formula, where R and R′ are the aryl or alkyl groups. There are two types of ethers. A simple or symmetrical ether, for example, is one in which the alkyl groups on both sides of an oxygen atom are the same. Mixed or unsymmetrical ethers, on the other hand, are defined as ethers that are not symmetrical.
The solvent and anaesthetic diethyl ether, commonly known as “ether,” is a good example of the first group (CH3 – CH2 – O – CH2 – CH3). As common connections in lignin and carbohydrates, ethers are common in organic chemistry and even more so in biochemistry. Ethers have a structure that is similar to alcohol, and both alcohols and ethers have a structure that is similar to water. Ethers have the generic formula R-O-R, R-O-Ar, or Ar-O-Ar, with Ar denoting an aryl group and R denoting an alkyl group.
Chemical Reactions of Ether
Contact of ethers with air: Most aliphatic ethers progressively convert to unstable peroxides when exposed to air. The presence of peroxides is indicated by the production of red colour. When ether is shaken with an aqueous solution of ferrous ammonium sulphate and potassium thiocyanate, this colour occurs.
Ether Halogenation: The dark halogenation of ether produces halogenated ethers. The hydrogen atom connected to the C atom, which is directly related to the oxygen atom, is replaced by halogens.
Cleavage by HBr and HI: Ethers are generally non-reactive. Cleavage of the C-O bond occurs when an excess of hydrogen halide is added to the ether. Alkyl halides are produced as a result. The following is the reaction order.
Sample Questions(FAQs)
Question 1: What is meant by Alcohol, Phenol and Ether?
Answer:
Alcohol – Alcohols are substances that have a hydroxyl group (-OH) linked to a saturated carbon atom.
Phenol – An alkyl, alkynyl, cycloalkyl, or benzyl group could be the saturated carbon. Phenols, on the other hand, are chemicals that have a hydroxyl group connected to a benzene ring.
Ether – The ether group is an organic molecule that has an oxygen atom linked to two alkyl and aryl groups.
Question 2: How many isomers of C5H11OH will be primary alcohols?
When phenols are treated with bromine in the presence of a low-polarity solvent such CHCl3 at low temperatures, mono-bromo phenol is formed.
Question 4: What is the distinction between ether and alcohol?
Answer:
The hydroxyl group of phenol connects directly to an aromatic ring carbon atom, whereas the hydroxyl group of alcohols attaches to a saturated carbon atom.
Question 5: Write Alcohol’s Oxidation Reactions.
Answer:
Primary Alcohol: A primary alcohol is easily oxidized to generate an aldehyde, which is followed by a carboxylic acid. The aldehyde and acid that result have the same number of carbon atoms as the parent alcohol.
Secondary Alcohol: With chromic anhydride, secondary alcohol can be quickly converted to a ketone. Under extreme conditions, the ketone might be further oxidized to produce an acid mixture.
Tertiary Alcohol: Because there is no hydrogen in the carbon-bearing hydroxyl group, tertiary alcohol is extremely difficult to oxidize (OH). When exposed to acidic oxidizing chemicals under very strong circumstances at very high temperatures, cleavage of various C-C bonds occurs, allowing for the oxidation of tertiary alcohol.
Neeraj Anand, Param Anand
Er. Neeraj K.Anand is a freelance mentor and writer who specializes in Engineering & Science subjects. Neeraj Anand received a B.Tech degree in Electronics and Communication Engineering from N.I.T Warangal & M.Tech Post Graduation from IETE, New Delhi. He has over 30 years of teaching experience and serves as the Head of Department of ANAND CLASSES. He concentrated all his energy and experiences in academics and subsequently grew up as one of the best mentors in the country for students aspiring for success in competitive examinations.
In parallel, he started a Technical Publication "ANAND TECHNICAL PUBLISHERS" in 2002 and Educational Newspaper "NATIONAL EDUCATION NEWS" in 2014 at Jalandhar. Now he is a Director of leading publication "ANAND TECHNICAL PUBLISHERS", "ANAND CLASSES" and "NATIONAL EDUCATION NEWS".
He has published more than hundred books in the field of Physics, Mathematics, Computers and Information Technology. Besides this he has written many books to help students prepare for IIT-JEE and AIPMT entrance exams. He is an executive member of the IEEE (Institute of Electrical & Electronics Engineers. USA) and honorary member of many Indian scientific societies such as Institution of Electronics & Telecommunication Engineers, Aeronautical Society of India, Bioinformatics Institute of India, Institution of Engineers. He has got award from American Biographical Institute Board of International Research in the year 2005.
Below is the CBSE Class 12 Syllabus along with the marking scheme and time duration of the Chemistry exam.
S.No
Title
No. of Periods
Marks
1
Solutions
10
7
2
Electrochemistry
12
9
3
Chemical Kinetics
10
7
4
d -and f -Block Elements
12
7
5
Coordination Compounds
12
7
6
Haloalkanes and Haloarenes
10
6
7
Alcohols, Phenols and Ethers
10
6
8
Aldehydes, Ketones and Carboxylic Acids
10
8
9
Amines
10
6
10
Biomolecules
12
7
Total
70
CBSE Class 12 Chemistry Practical Syllabus along with Marking Scheme
The following is a breakdown of the marks for practical, project work, class records, and viva. The total number of marks for all parts is 15. The marks for both terms are provided in the table below.
Evaluation Scheme for Examination
Marks
Volumetric Analysis
08
Salt Analysis
08
Content-Based Experiment
06
Project Work and Viva
04
Class record and Viva
04
Total
30
CBSE Class 12 Chemistry Syllabus (Chapter-wise)
Unit -1: Solutions
Raoult's law.
Colligative properties - relative lowering of vapour pressure, elevation of boiling point, depression of freezing point, osmotic pressure, determination of molecular masses using colligative properties, abnormal molecular mass.
Solutions, Types of solutions, expression of concentration of solutions of solids in liquids, solubility of gases in liquids, solid solutions.
Van't Hoff factor.
Unit -2: Electrochemistry
Redox reactions, EMF of a cell, standard electrode potential
Nernst equation and its application to chemical cells
Relation between Gibbs energy change and EMF of a cell
Kohlrausch's Law
Electrolysis and law of electrolysis (elementary idea)
Dry cell-electrolytic cells and Galvanic cells
Conductance in electrolytic solutions, specific and molar conductivity, variations of conductivity with concentration.
Lead accumulator
Fuel cells
Unit -3: Chemical Kinetics
Rate of a reaction (Average and instantaneous)
Rate law and specific rate constant
Integrated rate equations and half-life (only for zerfirst-order order reactions)
Concept of collision theory (elementary idea, no mathematical treatment)
Factors affecting rate of reaction: concentration, temperature, catalyst;
Order and molecularity of a reaction
Activation energy
Arrhenius equation
Unit -4: d and f Block Elements
Lanthanoids- Electronic configuration, oxidation states, chemical reactivity and lanthanoid contraction and its consequences.
Actinoids- Electronic configuration, oxidation states and comparison with lanthanoids.
General introduction, electronic configuration, occurrence and characteristics of transition metals, general trends in properties of the first-row transition metals – metallic character, ionization enthalpy, oxidation states, ionic radii, color, catalytic property, magnetic properties, interstitial compounds, alloy formation, preparation and properties of K2Cr2O7 and KMnO4.
Unit -5: Coordination Compounds
Coordination compounds - Introduction, ligands, coordination number, color, magnetic properties and shapes
The importance of coordination compounds (in qualitative analysis, extraction of metals and biological system).
IUPAC nomenclature of mononuclear coordination compounds.
Bonding
Werner's theory, VBT, and CFT; structure and stereoisomerism
Unit -6: Haloalkanes and Haloarenes
Haloarenes: Nature of C–X bond, substitution reactions (Directive influence of halogen in monosubstituted compounds only). Uses and environmental effects of - dichloromethane, trichloro methane, tetrachloromethane, iodoform, freons, DDT.
Haloalkanes: Nomenclature, nature of C–X bond, physical and chemical properties, optical rotation mechanism of substitution reactions.
Unit -7: Alcohols, Phenols and Ethers
Phenols: Nomenclature, methods of preparation, physical and chemical properties, acidic nature of phenol, electrophilic substitution reactions, uses of phenols.
Ethers: Nomenclature, methods of preparation, physical and chemical properties, uses.
Alcohols: Nomenclature, methods of preparation, physical and chemical properties (of primary alcohols only), identification of primary, secondary and tertiary alcohols, mechanism of dehydration, and uses with special reference to methanol and ethanol.
Unit -8: Aldehydes, Ketones and Carboxylic Acids
Carboxylic Acids: Nomenclature, acidic nature, methods of preparation, physical and chemical properties; uses.
Aldehydes and Ketones: Nomenclature, nature of carbonyl group, methods of preparation, physical and chemical properties, mechanism of nucleophilic addition, the reactivity of alpha hydrogen in aldehydes, uses.
Unit -9: Amines
Diazonium salts: Preparation, chemical reactions and importance in synthetic organic chemistry.
Amines: Nomenclature, classification, structure, methods of preparation, physical and chemical properties, uses, and identification of primary, secondary and tertiary amines.
Unit -10: Biomolecules
Proteins -Elementary idea of - amino acids, peptide bond, polypeptides, proteins, structure of proteins - primary, secondary, tertiary structure and quaternary structures (qualitative idea only), denaturation of proteins; enzymes. Hormones - Elementary idea excluding structure.
Vitamins - Classification and functions.
Carbohydrates - Classification (aldoses and ketoses), monosaccharides (glucose and fructose), D-L configuration oligosaccharides (sucrose, lactose, maltose), polysaccharides (starch, cellulose, glycogen); Importance of carbohydrates.
Nucleic Acids: DNA and RNA.
The syllabus is divided into three parts: Part A, Part B, and Part C. Part A consist of Basic Concepts of Chemistry, which covers topics such as atomic structure, chemical bonding, states of matter, and thermochemistry. Part B consists of Topics in Physical Chemistry, which includes topics such as chemical kinetics, equilibrium, and electrochemistry. Part C consists of Topics in Organic Chemistry, which covers topics such as alkanes, alkenes, alkynes, and aromatic compounds.
Basic Concepts of Chemistry:
Atomic structure: This section covers the fundamental concepts of atomic structure, including the electronic configuration of atoms, the Bohr model of the atom, and the wave nature of matter.
Chemical bonding: This section covers the different types of chemical bonds, including ionic, covalent, and metallic bonds, as well as the concept of hybridization.
States of the matter: This section covers the three states of matter - solid, liquid, and gas - and the factors that influence their properties.
Thermochemistry: This section covers the principles of thermochemistry, including the laws of thermodynamics and the concept of enthalpy.
Chapters in Physical Chemistry:
Chemical kinetics: This section covers the study of the rate of chemical reactions and the factors that influence it, including the concentration of reactants, temperature, and the presence of catalysts.
Equilibrium: This section covers the principles of chemical equilibrium, including the concept of Le Chatelier's principle and the equilibrium constant.
Electrochemistry: This section covers the principles of electrochemistry, including the concept of half-cell reactions, galvanic cells, and electrolysis.
Chapters in Organic Chemistry:
Alkanes: This section covers the properties and reactions of alkanes, including their structure, isomerism, and combustion.
Alkenes: This section covers the properties and reactions of alkenes, including their structure, isomerism, and addition reactions.
Alkynes: This section covers the properties and reactions of alkynes, including their structure, isomerism, and addition reactions.
Aromatic compounds: This section covers the properties and reactions of aromatic compounds, including their structure, isomerism, and electrophilic substitution reactions.
In addition to the topics covered in the syllabus, the CBSE Class 12 Chemistry exam also tests students on their analytical and problem-solving skills, as well as their ability to apply the concepts learned in the classroom to real-world situations.
Students can also check out the Tips for the Class 12 Chemistry Exam. They can easily access the Class 12 study material in one place by visiting the CBSE Class 12 page at ANAND CLASSES (A School Of Competitions). Moreover, to get interactive lessons and study videos, download the ANAND CLASSES (A School Of Competitions) App.
Frequently Asked Questions on CBSE Class 12 Chemistry Syllabus
Q1
How many chapters are there in the CBSE Class 12 Chemistry as per the syllabus?
There are 10 chapters in the CBSE Class 12 Chemistry as per Syllabus. Students can learn all these chapters efficiently using the study materials provided at ANAND CLASSES (A School Of Competitions).
Q2
What is the marking scheme for CBSE Class 12 Chemistry practical exam according to the syllabus?
The marking scheme for CBSE Class 12 Chemistry practical exam, according to the syllabus, is 8 marks for volumetric analysis, 8 marks for salt analysis, 6 marks for the content-based experiment, 4 marks for the project and viva and 4 marks for class record and viva.
Q3
Which is the scoring chapter in Chemistry as per CBSE Class 12 syllabus?
The chapter Electrochemistry in Chemistry is the scoring chapter as per CBSE Class 12 syllabus.
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