Read Every Day 10 Points and Think of the other points that are implied by them.
This process will help you to complete intensive study of all the concepts of the subject by the time you appear for JEE Main in April 2020.
12 January 2019
Haloalkanes and HaloarenesJEE Syllabus
UNIT 22: ORGANIC COMPOUNDS CONTAINING HALOGENS
General methods of preparation, properties and reactions; Nature of C-X bond; Mechanisms of substitution reactions. Uses; Environmental effects of chloroform - iodoform.
1. The groups which possess two nucleophilic centres are called ambident nucleophiles.
Explanation: An ambident nucleophile has "teeth" on two sides.
It can attack from two different places and form two different products.
For example, the thiocyanate ion, SCN⁻, is a ambident nucleophile. It is a resonance hybrid.
Both the S and the N atoms can act as nucleophiles.
R-X+SCN⁻→X⁻ + R-SCN + R-NCS
2. The rate of reaction depends on the concentration of both alkyl halid and base, the reation is known as SN2 reactions.
3. The rate of reaction depends on the concentration of alkyl halides, the reaction is known as SN1 reaction.
4. The order of reactivity of alkyl halides for SN1 reactions
3 degree halide > 2 degree halide > 1 degree halide > CH3X
(tertiary) (secondary) (primary)
5. The order of reactivity of alkyl halides for SN2 reactions
3 degree halide < 2 degree halide < 1 degree halide < CH3X
6. In SN1 and SN2 mechanism, the reactivity of halides follows the order
R-I > R-Br > R-Cl > R-F
7. If all the substituents attached to a carbon are different, that carbon is called asymmetric (or) Chiral carbon or stereocentre.
8. The stereo isomers related to each other as non-super imposable images are called enantiomers.
9. A mixture containing two enantiomers in equal proportions will have zero optical rotation, as the rotation due to one isomer will be exactly cancelled by the rotation due to the other isomer. Such a mixture is known as racemic mixture or racemic modification.
10. The process of conversion of enantiomer into a racemic mixture is known as racemisation.
Key words: ambident nucleophiles, SN2 reactions, SN1 reaction, The order of reactivity of alkyl halides for SN1 reactions (degree of halides), The order of reactivity of alkyl halides for SN2 reactions(degree of halides), order of reactivity of halides (based on halogen), asymmetric (or) Chiral carbon or stereocentre, enantiomers, racemic mixture or racemic modification, racemisation.
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11. SN2 reactions of optically active halides are accompanied by inversion of configuration.
12. SN1 reactions are accompanied by racemisation.
13. Finkelstein reaction - The reaction of alkyl chloride (or) bromide with NaI in dry acetone gives Alkyl iodides.
14. Swarts reaction -The reaction of alkyl chloride (or) bromide with metal flourides like AgF, Hg2F2, CoF2, SbF3 on heating gives alkyl fluorides.
15. Haloalkane reacts with KCN to form alkyl cyandie as main product where haloalkane reacts with AgCN to form alkyl isocyanide as the main product.
16. Sandmeyer's reaction - The reaction of benzene diazonium salt with cuprous chloride (or) bromide and HCl gives chlorobenzene or bromobenzene.
Reactions of Cholorobenzene
17. Cholorobenzene reacts with chlorine in presence of AlCl2 gives 1,4-dichlorobenzene as a major product, and 1,2 -dichlorobenzene as a minor product.
18. Cholorobenzene reacts with nitration mixture and gives 1-chloro-4-nitrobenzene as a major product and 1-chloro-2-nitrobenzene as a minor product.
19. Cholorobenzene reacts with CH3Cl in presence of AlCl3 adn gives 1-chloro-4-methylbenzene as a major product and 1-chloro-2-methyl benzene as a minor product.
20. Cholorobenzene reacts with CH3COCl in presence of AlCl3 and gives 4-chloro-acetophenone as a major product and 2-chloro-acetophenone as a minor product.
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21. Fittig reaction: Cholorobenzene reacts with sodium in presence of dry ether - gives diphenyl.
22. Wurtz-Fittig reaction: Cholorobenzene, alkyl halide and sodium react in presence of dry ether and give alkyl benzene.
23. DDT = P, p1-dichlorodiphenyltrichloroethane
24. Grignard reagent (RMgX): Obtained by the reaction of haloalkanes with magnesium metal in dry ether.
25. Freons (CCl2F2) are chlorofluoro compounds of methane and ethane.
26. In dehydrohalogenation reactions, the preferred product is that alkene which has the greater number of alkyl groups attached to the doubly bonded carbon atoms.
Organic Compounds with Functional Groups OH and CHOJEE Syllabus
UNIT 23: ORGANIC COMPOUNDS CONTAINING OXYGEN
General methods of preparation, properties, reactions and uses
ALCOHOLS, PHENOLS AND ETHERS
Alcohols: Identification of primary, secondary and tertiary alcohols; mechanism of dehydration.
Phenols: Acidic nature, electrophilic substitution reactions: halogenation, nitration and sulphonation, Reimer – Tiemann reaction.
Aldehyde and Ketones: Nature of carbonyl group;Nucleophilic addition to >C=O group, relative reactivities of aldehydes and ketones; Important reactions such as – Nucleophilic addition reactions (addition of HCN, NH3 and its derivatives), Grignard reagent; oxidation; reduction (Wolff Kishner and Clemmensen); acidity of α – hydrogen, aldol condensation, Cannizzaro reaction, Haloform reaction; Chemical tests to distinguish between aldehydes and Ketones.
Carboxylic acids: Acidic strength and factors affecting it.
Alcohols and Phenols
1. Methanol (CH3OH) is referred to as wood spirit.
Alcohol from alkenes
2. Alkenes react with water in the presence of acid as catalyst to form alcohols.
Mechanism of alcohol formation
3. Protonation of alkene to form carbocation by electrophylic attack of H3O+.
4. Nucleophylic attack of water on carbocation.
5. Deprotonation to form an alcohol
Key words: Fittig reaction, Wurtz-Fittig, DDT, Grignard reagent , Freons, preferred product in dehydrohalogenation reactions of halides, wood spirit., Alcohol from alkenes ,
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6. Diborane (BH3)2 reacts with alkenesto give trialkyl boranes as addition product.
7. Trialkyl borane is oxidized to alcohol by hydrogen peroxide in the presence of acqueous sodium hydroxide.
8. With sodium borohydride (NaBh4) or lithiumaluminium hydride (LiAlH4), aldehydes yield primary alcohols. Ketones give secondary alcohols.
9. Primary (1 degree), secondary (2 degree) and tertiary (3 degree) alcohols are distinguished by Lucas test.
Preparation of Phenol
10. Chlorobenzene is fused with NaOH at 623K and 320 atmospheric pressure. ... Phenol is obtained by acidification of sodium phenoxide.
11. Benzene is sulphonated with oleum and benzene sulphonic is acid formed. The acid is converted to sodium phenoxide on heating with molten sodium hydroxide. Phenol is obtained by acidification of sodium phenoxide.
High boiling points of alcohols
12. The high boiling points of alcohols are mainly due to the presence of intermolecular hydrogen bonding in them which is not present in ethers and hydrocarbons.
13. Propanol has higher boiling point than that of hydrocarbon n-butane due to intermolecular hydrogen bond.
Solubility of alcohols and phenols
14. Solubility of alcohols and phenols in water is due to their ability to form hydrogen bonds with water molecules.
15. The solubility decreases with increase in size of alkyl/aryl groups. Several lower molecular mass alcohols are misible with water in all proportions.
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Acidic nature of phenol.
16. The reactions of phenol with metals (sodium, alumimium) and sodium hydroxide indicate its acidic nature.
For details read: Acidic nature of phenols
17. The hydroxyl group, in phenol is directly attached to the sp2 hybridized carbon of benezene ring which acts as an electron withdrawing group.
18. The reaction of phenol with acqueous sodium hydroxide indicates that phenols are stronger acids than alcohols and water.
19. Due to the higher electronegativity of sp2 hybridised carbon of phenol to which -OH is attached electron density decreases on oxygen.
20. The presence of electron withdrawing groups such as nitro group, enhances the acidic strength of phenol.
21. The effect is more pronounced when withdrawing group is present at ortho and para positions. It is due to the effective delocalisation of negative charge in phenoxide ion.
22. Strong oxidizing agents such as potassium permanganate are used for getting carboxylic acids from alcohols directly.
23. CrO3 in anhydrous medium is used as the oxidizing agent for the isolation of aldehydes.
24. A better reagent for oxidation of primary alcohols to aldehydes in good yield is pyridium chlorochromate (PCC), a complex of chromium trioxide with pyridine and HCl.
25. The -OH group attached to the benzene ring activates it towards electrophilic sustituion. 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.
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26. The ortho and para isomers can be separated by steam distillation.
27. Kolbe's reaction: Phenol is treated with sodium hydroxide and carbon dioxide to from salicylic acid.
28. Reimer - Tiemann reaction:Phenol reacts with chloroform in the presence of sodium hydroxide to form salicylaldehyde.
29. Reduction of phenol with zinc dust forms benzene.
30. Oxidation of phenol with chromic acid produces a conjugated diketone known as benzoquinone.
31. Williamson synthesis:
32. Anisole reacts with the alkylhalide and acyl halide in the presence of anhydrous aluminium chloride as catalyst. The alkyl and acyl groups are introduced at ortho and para positions in the resultant products.
33. Nitration: Anisole reacts with a mixture of concentrated sulphur amd nitric acid to yield a mixture of ortho and para nitroanisole.
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Aldehydes, Ketones and Carboxylic Acids
1. Friedel-craft acylation: Benzene is treated with acetylchloride in the presence of AlCl3 to form acetophenone.
2. Cannizaro reaction: Aldehydes which do not have α-hydrogen atom react with concentrated sodium hydroxide (NaOH) or potassium hydroxide (KOH) in such a way that one molecule get oxidized to acid and the second molecule gets reduced to alcohol.
Note two molecules of aldehyde participates in the reaction.
This self oxidation-reduction under the influence of a base is known as the Cannizzaro's reaction.
Formaldehyde does not possess α-hydrogen atom and therefore undergoes Cannizzaro's reaction. Acetaldehyde does not give this reaction.
3. Aldol Condensation: Aldehydes and ketones containing α-hydrogen (H-atoms attached to the C-atom adjacent to the carbonyl group)undergo condensation in the presence of dilute alkali.
In the resulting compound both aldehyde group and alcohol group are present.
acetaldehyde and acetone undergo aldol condensation.
Formaldehyde, banzaldehyde do not undergo aldol condensation.
4. Cross aldol condensation: Aldol condensation carried out between different aldehydes (or) ketones. In this process 4 products are obtained.
5. Acid salts are heated with sodalime loose CO2 to form hydrocarbons.
6. HVZ reaction:
7. Carbonyl compounds participate in nucleophylic addition reactions.
8. Carbonyl compounds are treated with HCN to form Cynohydrins.
9. Aldehydes react with one molecule of alcohol in the presence of dry HCL and form alkoxy alcohols. It is called hemiacetal.
10. Aldehydes react with two molecules of alcohol and form dialkoxy compounds. It is called acetal.
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11. Formation of semicarbozone:
12. Formation of oxime:
JEE Syllabus topic: Carboxylic acids: Acidic strength and factors affecting it.
13. Presence of electron withdrawing groups increases acidic nature of Carboxylic Acids.
14. Presence of electron releasing groups decreases acidic nature of Carboxylic Acids
15. Feling's reagent.
16. Fehling test
17. Tollen's reagent
18. Tollen's test
19. In benzoic acid electrophylic substitution takes place at meta position.
20. Acetic acid is treated with PCl3/PCl5 to form Benzamide.
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21. Formation of Benzamide
22. Increasing order of acidic strength of various benzoic acids.
23. Decreasing order of acidic strength of given carboxilic acids
Organic Compounds Containing Nitrogen - Amines
UNIT 24: ORGANIC COMPOUNDS CONTAINING NITROGEN
General methods of preparation, properties, reactions and uses
Amines: Nomenclature, classification, structure, basic character and identification of primary, secondary and tertiary amines and their basic character.
Diazonium Salts: Importance in synthetic organic chemistry.
1. What are amines?
2, Preparation of aniline.
4. Reactity of halides with amines - order
5. Primary amines from nitriles
6. Primary amines from amides
7. Gabriel phthalimid synthesis
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8. Hoffman bromamide degradation reaction.
9. Boiling points of different amines.
10. Order of basic nature of amine (Remember acidic nature of phenols)
11. Amines behave as Lewis bases.
12. Alkylation of amines.
13. Acetylation of amines.
14. Benzoylation of amines
15. Carbylamine reaction
16. Amines - nitrous acid reation
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18. Hinsberg reagent
19. Formation of sulphonamide
20. reaction of tertiary amines
21. Ortho and para directing and ring activating group
22. 2,4,6, tri bromo aniline formation
23. Nitration reaction of aniline
25. Aniline and Friedal crafts reaction
26. Benzene diazonium chloride.
27. Diazonium salt general formula
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29. Gatterman reaction
1. Formation of cyanides - Aldoximes are dehydrated by acetic anhydride.
2. Hydrolysis of isocyanides
3. Cyanides reaction with Grignard reagent.
4. Cyanides reaction with LiAlH4
5. Ioscyanides reduction with H2/Ni
6. Oxidation of isocynaides
24 January 2020
General Principles of Metallurgy
7. Concentration of Ore
8. Froth flotation process
10. Roasting: Process of heating in presence of air.
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13. Blast furnace - Chemical reactions
14. Extraction of coppoer from copper pyrites
15. Electrolytic refining of copper
16. Ore of aluminium
17. Electrolytic reduction of pure alumina.
18. General methods of refining
19. Role of cryolite
20. Fractional crystallization
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21. Vapour phase refining
22. Composition of alloys. - Brass
23. Uses of metal zinc
24. Uses of metal copper
25. Uses of metal iron
26. Uses of metal aluminium
27. Uses of cast iron
28. Uses of wrought iron
29. Uses of nickel steel
30. Uses of stainless
27 January 2020
Updated 20 January 2020, 17 January 2020,