Alcohol, phenol, and ether compounds have a wide range of industrial and home uses. Alcohol is formed when the hydroxyl (-OH) group binds to a saturated carbon atom. Ether is formed when alcohol is dehydrated. Based on the hydroxyl group, there are three kinds of alcohol: monohydric, dihydric, and trihydric.
In hydrocarbon, when we replace one or more hydrogen with another group or groups of atoms a new substance is formed which is completely different from the previous compound. So in that manner, the organic compound in which one or more hydrogen atoms are replaced by hydroxyl groups are termed as alcohols or phenols. Hydroxyl derivatives of aliphatic hydrocarbons are alcohol whereas phenols are hydroxyl derivatives of aromatic hydrocarbons in which the hydroxyl group is directly attached to the carbon atom of the aromatic ring. However, the organic compounds in which the hydrogen atom of a hydrocarbon (aliphatic or aromatic) replace by an alkoxy (OR) or aryloxy(OAR) group are known as ethers.
Table of Contents
What are Alcohols ?
Alcohols are chemical molecules in which the -OH group or hydroxyl group replaces the hydrogen atom of an aliphatic carbon. As a result, an alcohol molecule is made up of two parts: one with the alkyl group and the other with the hydroxyl group. It’s written as R-OH, with R denoting the alkyl group.
The most well-known alcohol is ethanol, also known as ethyl alcohol, which is widely used in alcoholic beverages, as a preservative for biological specimens, as fuel (gasoline), and as a drug and paint solvent.
The suffix -ol is used to the parent chain of the alkane name when designating alcohols. The -OH functional group’s location is specified in the name. The parent chain is numbered at the end nearest to where the -OH is placed. CnH2n+1OH is the general formula for alcohol homologous series, where n=1, 2, 3,…
Classification of Alcohols
Depending on how many –OH groups are connected to the carbon atom chain, alcohols can be classified into two different classes:
On the basis of the carbon atoms that are linked to the hydroxyl group: The carbon and oxygen atoms are sp3 hybridized in all of these kinds.
Primary (1°) Alcohols – The chemical is primary alcohol if the -OH group is connected to a primary carbon atom (1°, coupled to just one other carbon atom). As a result, the carbon atom carrying the -OH group is only connected to one neighbouring alkyl group. Primary alcohols include the following: ethanol, propan 1-ol, 2 methylpropan 1-ol, etc.
Secondary (2°) Alcohols – When the -OH group is connected to a secondary carbon atom (2°, which is coupled to two additional carbon atoms), the chemical is classified as secondary alcohol. As a result, the carbon atom carrying the -OH group is directly connected to two neighbouring alkyl groups, which may be the same or different. The following are some examples: propan 2-ol, butan 2-ol, etc.
Tertiary (3°) Alcohols – The compound is tertiary alcohol if the -OH group is connected to a tertiary carbon atom (3°, bonded to three additional carbon atoms). As a result, the carbon atom bearing the -OH group is directly bonded to three neighbouring alkyl groups that can be any combination of the same or different groups. Tertiary alcohols can be found in the following forms: 2 – methylpropan 2-ol, etc.
Alcohols are categorised into three types based on the number of hydroxyl groups attached:
Monohydric Alcohols – Monohydric alcohols are those with only one hydroxyl group in their molecules. The kind of hybridisation of the carbon atom to which the hydroxyl group is connected further categorises monohydric alcohols as,
Alcohols containing C (sp2)–OH bond (Vinylic alcohols): The –OH group is connected to an sp2 hybridised carbon atom, such as vinylic carbon, in these monohydric alcohols. Vinylic alcohols are another name for these alcohols.
Alcohols containing C (sp3) – OH bond:
Benzylic Alcohols are the alcohols in which the -OH group is linked to the carbon that is sp3 hybridised which is present next to the aromatic ring. e.g. phenyl methanol, etc.
Allylic Alcohols are the alcohols in which the hydroxyl group is attached to the sp3 hybridised carbon atom next to the carbon-carbon double bond, i.e., allylic carbon. Allylic alcohol may be primary, secondary and tertiary alcohols.
Dihydric Alcohols – Dihydric alcohols are alcohols with two hydroxyl groups in their molecules. Propylene glycol is an example of dihydric alcohol.
Trihydric Alcohols – Trihydric alcohols are alcohols with three hydroxyl groups in their molecules. Glycerol, for example.
What is Phenol ?
Phenol is a hydroxyl compound that is organic, aromatic and has one or more hydroxyl groups directly linked to the aromatic ring. C6H5OH is the chemical formula for phenol. It is a moderately acidic white crystalline substance that occurs as a byproduct of coal tar distillation. It’s a hygroscopic and volatile liquid. It has a sweet aroma and a harsh scorching flavour. It is utilised in the production of a wide range of vital goods, including polymers and antiseptics.
Classification of Phenol
Phenols are categorised into three categories based on the amount of hydroxyl (–OH) groups connected to the aromatic ring.
Monohydric phenols: Monohydric phenols are phenols with only one hydroxyl (–OH) group. e.g. O-cresol, etc.
Dihydric phenols: Dihydric phenols are phenols with two hydroxyls (–OH) groups. The phenols can be ortho, meta, or para derivatives. e.g. Catechol, Resorcinol, etc.
Trihydric phenols: Trihydric phenols are phenols with three hydroxyls (–OH) groups. e.g. Benzene- 1, 2, 3-triol.
What are Ethers ?
Ethers are a type of organic molecule in which two hydrocarbon groups (alkyl or aryl) are linked together by a single oxygen atom. The R-O-R′ formula is used to express it. The hydrocarbon group in the formula, R′, might be the same as or different from R. Ethers are formed when the hydrogen atom of an alcohol’s hydroxyl group is replaced with an alkyl or aryl group.
Classification of Ethers
Ethers are categorized as simple or symmetrical ethers depending on the alkyl or aryl group attached to an oxygen atom.
Symmetrical Ethers – If the two alkyl or aryl groups attached to the oxygen atom are the same is known as symmetrical ethers.
e.g. CH3-O-CH3 (Dimethyl ether), CH3CH2-O-CH2CH3 (Diethyl ether). C6H5-O-C6H5 (Diphenyl ether), etc.
Unsymmetrical ethers – If the two groups attached to the oxygen atom are different and is known as unsymmetrical ethers.
e.g. CH3-O-CH2CH3 (Ethyl methyl ether), C6H5-O-CH3 (Methyl phenyl ether), C6H5-O-CH2C6H5 (Benzyl phenyl ether), etc.
Sample Questions (FAQs)
Question 1: How to differentiate between alcohol, phenol and ethers?
Answer:
In the case of alcohol (OH) group means a hydroxyl group attached to a carbon atom and in phenol hydroxyl group attached to benzene ring while in ether two carbon groups are attached by a single bond with oxygen.
Question 2: State whether phenol is an acid or a base?
Answer:
The nature of the phenol is acidic as it has a tendency to the hydrogen ions from its OH bond, after closing the hydrogen phenoxide ion is formed which is more stable.
Question 3: Why ethers are less dense than alcohols?
Answer:
As there is no hydrogen bond formed by ethers and has more boiling point than those of which forms hydrogen bond i.e., alcohols. So ethers are less dense than alcohols.
Question 4: What do you mean by denatured alcohol?
Answer:
The change in the property of alcohol referred to products adulterated with toxic additives which are unsuitable for the consumption of humans.
Question 5: In alcohol or phenol which is more soluble in water and why?
Answer:
Both alcohol and phenol are soluble in water as bonds can form hydrogen bonds with water but due to the presence of benzene ring means containing a large hydrocarbon group the solubility of phenol is less than 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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