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ALCOHOLS, PHENOLS AND ETHERS | Complete Chapter in 1 Shot | Class 12th Board-NCERT

NCERT Wallah・2 minutes read

The session covers alcohol, final, and ether basics with definitions and examples, including classification, naming, preparation methods, and chemical properties. It emphasizes understanding reactions and classifications for comprehensive learning and retention.

Insights

  • Alcohol, final, and ether are distinct organic compounds with unique structures and characteristics.
  • Classification of alcohols is based on the number of OH groups present, leading to monohydric, dihydric, and trihydric compounds.
  • The hybridization of carbon atoms attached to OH groups dictates the classification of primary alcohols.
  • Nomenclature of compounds involves identifying functional groups, parent chain carbon atoms, and prioritizing the highest functional group.
  • Chemical properties of alcohols include acting as both electrophiles and nucleophiles, impacting their reactivity in various reactions.

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Recent questions

  • What is the definition of alcohol?

    Alcohol is defined by the presence of an OH group in an organic compound, with examples like CH3OH.

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Summary

00:00

"Alcohol, Final, Ether: Definitions and Examples"

  • The session is on Alcohol Final and Ether, starting with an introduction and thumbs up from students.
  • The session will cover the basics of alcohol, final, and ether, focusing on their definitions and examples.
  • Alcohol is defined by the presence of an OH group in an organic compound, with examples like CH3OH.
  • Final is characterized by an OH group attached to an aromatic ring, exemplified by structures like benzene rings.
  • Ether is represented by replacing a hydrogen in a hydrocarbon with an OR group, with examples like ROR'.
  • Classification of alcohols includes monohydric, dihydric, and trihydric compounds based on the number of OH groups present.
  • Monohydric alcohols have a single OH group, dihydric have two, and trihydric have three, with examples like glycerol.
  • Further classification involves monohydric primary alcohols based on the hybridization of the carbon atom attached to the OH group.

17:01

"Chemistry: Hybridization, Alcohol Classification, and Mistakes"

  • Han Ji is cleared, which is positive.
  • Vinyl cases are a current concern, caution is advised.
  • Mono detritus classification is now mono, as per Wardha.
  • Basis for attacking Hydra is the carbon's hybridization with the OH group.
  • Hybridization check is crucial, focusing on the carbon to which the OH group is attached.
  • Sigma bonds and lone pairs determine hybridization, not bond counting.
  • Hybridization rules dictate SP3 for four bonds, SP2 for three, and SP for two.
  • Emphasis on learning from mistakes, especially in solving questions.
  • Primary, secondary, and tertiary alcohol classification based on carbon degree.
  • Benzylic alcohol is identified by the OH group's attachment to a sp3 hybridized carbon connected to a benzene ring.

31:03

Determining Carbon Connection in Functional Groups

  • The degree of carbon must be checked to determine the connection of the OH group.
  • The OH group is attached to a carbon with sp3 hybridization.
  • The carbon to which the OH group is attached should have sp2 hybridization.
  • Vinyl alcohol is an example where the OH group is connected to a carbon making a double bond.
  • Ether is classified into symmetrical and unsymmetrical categories based on the groups attached to oxygen.
  • Symmetrical ether has the same groups on both sides of oxygen, while unsymmetrical ether has different groups.
  • The IUPAC naming of compounds involves identifying the functional groups and the parent chain's carbon atoms.
  • The primary prefix indicates the type of bond in the carbon, while the secondary prefix denotes the functional group.
  • In naming compounds, the functional group with the highest priority is mentioned first.
  • Nomenclature of compounds involves identifying the word root, functional groups, and the position of substituents on the parent chain.

44:26

"Symmetrical Ether and Alcohol Preparation Methods"

  • Ether is classified into two categories: symmetrical ether and unsymmetrical ether.
  • Symmetrical ether is named as dialkyl ether in common terms and alkoxy alkane in IUPAC nomenclature.
  • An example of symmetrical ether is given as CH3OCH3, known as dimethyl ether in common terms and methoxy methane in IUPAC.
  • Another example is provided with the structure CH3OC2H5, named ethyl methyl ether in common terms and methoxy ethane in IUPAC.
  • The structure of a compound with the formula X3Y is discussed, emphasizing the arrangement of carbon atoms and halogens.
  • The method of preparation of alcohol through alkyl halide is explained, involving nucleophilic substitution reactions.
  • The nucleophile attacks the alkyl halide, leading to the formation of alcohol.
  • The concept of nucleophilic substitution reactions, nucleophiles, and electrophiles is elaborated upon.
  • The preparation of alcohol from alkynes through acid-catalyzed hydration is detailed, mentioning the reactions of hydroboration, oxidation, and oxymercuration-demercuration.
  • The application of Markovnikov's rule in acid-catalyzed hydration reactions with alkynes is highlighted.

59:32

"Alkyne Reactions: Marconikoff vs Anti-Marconi Rules"

  • The reaction involves ch2 ch2, with water present, leading to the formation of a product.
  • Marconikoff's rule is applied in this direct reaction, not the Anti-Marconi rule.
  • In an acidic catalyst, Marconikoff's rule is followed, with the negative part going to the carbon with fewer hydrogen atoms.
  • Symmetrical alkynes result in ch3 ch double bond ch2 when reacted with water.
  • Hydroboration oxidation involves adding water directly or indirectly, following Marconikoff's rule.
  • The mechanism of hydroboration oxidation includes breaking double bonds and forming new bonds with hydrogen atoms.
  • The oxidation step after hydroboration results in the formation of primary alcohol.
  • Indirect addition of water follows the Anti-Marconi rule, leading to ch3 ch2 ch2oh as the product.
  • Oxymercuration reaction involves mercury acetate and NaBH4, with no rearrangement occurring.
  • Carbonate compounds like aldehydes undergo reduction to form alcohols.

01:15:17

"Hydrogen catalytic reduction for organic synthesis"

  • Reduction is achieved through catalytic treatment with hydrogen in the presence of nickel, taking only 5 minutes to complete.
  • The process involves breaking bonds and releasing hydrogen, resulting in the formation of R-CH2.
  • Examples include the conversion of LIA to LH4 and BH4, with aldehydes yielding primary alcohols and ketones forming secondary alcohols.
  • The reaction with RMGX involves charging carbon more than oxygen, leading to the formation of RCOH.
  • Benzene reacts with chlorine to form chlorobenzene, with the reaction involving a positive-negative exchange.
  • The final product is obtained by reacting the negative R group with a positive species, resulting in the desired production.
  • Benzene sulfonic acid preparation is crucial, with a question related to it being significant.
  • Understanding the process of benzene sulfonic acid formation is essential for clarity and success in related questions.

01:28:48

Chemical Reactions and Properties of Alcohols

  • To create benzene, react oleum with oleum and benzene will react with SO3H to form benzene sulfonic acid.
  • Benzene sulfonic acid can be converted into sodium phenoxide by reacting with sodium hydroxide.
  • Diasunium salt is formed by reacting benzene with nitrous acid at a temperature between 273 to 278 Kelvin.
  • Aniline reacts with nitrous acid to form diasunium salt, which can then be reacted with CuCl to form chlorobenzene.
  • Cumin is oxidized in the presence of air to form cumin hydroperoxide, which can be converted to acetone by treating with dilute acid.
  • The boiling point of alcohols increases with an increase in the number of carbon atoms and decreases with an increase in branching.
  • Solubility of alcohols in water decreases with an increase in the size of the alkyl group due to hydrophobic nature.
  • Lower molecular weight alcohols are miscible with water due to their hydrophilic nature.
  • Chemical properties of alcohols involve them acting as both electrophiles and nucleophiles.
  • Marconi's rule dictates that charged species will behave as electrophiles or nucleophiles based on their charge.

01:55:03

Alcohol's Electrophilic and Nucleophilic Behavior

  • Alcohol exhibits both electrophilic and nucleophilic behavior in chemical properties.
  • Electrophiles are electron-loving species with a positive charge, while nucleophiles are nucleus-loving species with a negative charge.
  • In alcohol, the carbon-oxygen bond can break in two ways: the oxygen-hydrogen bond or the carbon-oxygen bond.
  • When the oxygen-hydrogen bond breaks, alcohol behaves as a nucleophile, attracting positively charged species.
  • If the carbon-oxygen bond breaks, alcohol acts as an electrophile, donating electrons to positively charged species.
  • Reacting alcohol with metals results in the liberation of H2 gas due to the formation of sodium alkoxide.
  • Acidity in alcohol involves donating a positive ion, resulting in the liberation of a positive charge and a negative charge.
  • The speed of acidity in alcohol is directly proportional to the electron-donating ability (I) and inversely proportional to the electron-withdrawing ability (M).
  • Understanding the acidity of alcohol is crucial for predicting its behavior in reactions and interactions.
  • The behavior of alcohol in reactions with metals and in acidity reactions provides valuable insights into its chemical properties and reactivity.

02:09:07

Alcohol Acidity and Reactivity in Chemistry

  • Acidity is inversely proportional, with more pluses indicating less acidity.
  • The order of acidity is primary, then secondary, and finally tertiary alcohols.
  • The inductive effect of Plus I groups impacts acidity.
  • Electron-releasing groups like CH3 and C2H5 increase electron density, reducing acidity.
  • Alcohol is less acidic than water due to the stability of the Anion.
  • Esterification reactions involve alcohol nucleophiles reducing carboxylic acids.
  • Alcohol behaves as an electrophile in reactions with hydrogen halides.
  • Reactions with phosphorus halides result in the formation of alkyl halides.
  • The reaction of alcohols with phosphorus pentachloride produces alkyl chlorides and phosphorus oxychloride.
  • Understanding and practicing reactions aids in retention and comprehension.

02:23:12

Understanding Organic Chemistry Reactions and Mechanisms

  • Repeating reactions help in connecting with negative hints and understanding nucleophilic substitution reactions.
  • Reading and repeating reactions multiple times ensures thorough understanding and retention.
  • Dehydration involves removing water molecules to form alkynes, illustrated with examples like ch3ch2oh.
  • Oxidation reactions with strong agents like kmno4 or k2cr2o7 lead to aldehyde formation from alcohols.
  • Secondary alcohols react with oxidizing agents to form ketones.
  • Reacting primary alcohols at 300°c produces aldehydes, while secondary alcohols yield ketones.
  • Phenol chemical reactions involve reactions with oh groups, leading to specific products like sodium phenoxide.
  • Nitration reactions with phenol and hno3 result in para products, influenced by dilution or concentration.
  • Friedel-Crafts alkylation reactions with phenol and ch3cl produce specific products at ortho and para positions.
  • Sulfonation reactions with phenol and concentrated h2so4 lead to specific products with so3h groups.

02:41:26

Organic Chemistry Reactions and Properties Explained

  • Sodium phenoxide is discussed in reactions, emphasizing its negative charge.
  • The reaction of sodium phenoxide with CO2 is highlighted, leading to the production of salicylic acid.
  • The reactivity of sodium phenoxide towards electrophilic aromatic substitution is mentioned.
  • The formation of ether through dehydration of primary alcohol with H2SO4 at specific temperatures is detailed.
  • The physical properties of ether, including its polar nature and boiling point in comparison to alcohols and hydrocarbons, are explained.
  • The cleavage of carbon-oxygen bonding in ether is discussed, particularly in reactions with PCl5.
  • The Williamson synthesis reaction involving alkyl halides and sodium alkoxide is outlined.
  • The preparation of methanol from methane through specific reactions is described.
  • The decomposition of sucrose into glucose and fructose in the presence of invertase is explained, leading to the production of ethanol.
  • The difference between basic and acidic organic compounds, based on the stability of anions and the presence of specific groups, is highlighted.

02:58:52

Chemical reactions and study tips for success.

  • Benzene ring reacts with Oleum to produce a specific product.
  • The reaction involves sodium and alcohol, with the final product being Atla.
  • The next question involves converting 2-methyl propane to methyl propanol using the hydroboration oxidation method.
  • Another question requires converting Benzyl Chloride to Benzyl Alcohol through acid catalysis.
  • The session concludes with a reminder to revise notes by dividing topics into segments and dedicating time to each for effective learning.
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