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Priya Sen

Scorching goIITian

Posted on 7 Jun 2007 19:38:20 IST

Topic : Review : Classification of Polymers

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0

519

Engineering Entrance , JEE Main

Classification of PolymersThermoplastic PolymersThese are linear, one-dimensional polymers which have strong intramolecular covalent bonds and weak intermolecular van Der Waals bonds. At elevated temperature, it is easy to "melt" these bonds and have molecular chains readily slide past one another. These polymers are capable of flow at elevated temperatures, can be remolded into different forms, and in general, are dissolvable. A thermoplastic, under the application of appropriate heat, can be melted into a "liquid" state. Thermosetting PolymersThese are three-dimensional amorphous polymers which are highly crosslinked (strong, covalent inte

Priya Sen

Scorching goIITian

Posted on 6 Jun 2007 23:24:02 IST

Topic : A few pts. on org reactions - PlZZZZZZZZZ have a look

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1193

Engineering Entrance , JEE Main

1. Acetoacetic-Ester CondensationClaisen CondensationThe Claisen Condensation between esters containing ?-hydrogens, promoted by a base such as sodium ethoxide, affords ?-ketoesters. The driving force is the formation of the stabilized anion of the ?-keto ester. If two different esters are used, an essentially statistical mixture of all four products is generally obtained, and the preparation does not have high synthetic utility.However, if one of the ester partners has enolizable ?-hydrogens and the other does not (e.g., aromatic esters or carbonates), the mixed reaction (or crossed Claisen) can be synthetically useful. If ketones or nitriles are used as the donor

Dinesh Babu

Blazing goIITian

Posted on 21 May 2007 12:23:15 IST

Topic : Aroma...!! ticity..! no 2

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6

790

Engineering Entrance , JEE Main

Identify the aromatic compounds from the following..........try this..!!! and rate me if u find it useful..!!

vag eeshwar

Hot goIITian

Posted on 28 May 2007 20:58:43 IST

Topic : THE acid

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0

713

Engineering Entrance , JEE Main

hough we consider H2SO4 / PERCHLORIC acid to be the strongest , THE STRONGEST ACID IS FLOUROANTIMONIC ACIDThe white sphere is the proton which is outside the SbF6- sphere. This makes the proton effectively naked and accounts for the extreme acidity.This acid is 10^19 times stronger than Sulphuric acid.according to a paper, this acid can produce solutions with a pH upto -25! 

Dinesh Babu

Blazing goIITian

Posted on 20 May 2007 22:32:11 IST

Topic : acidic strength..!

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3

622

Engineering Entrance , JEE Main

Tell me the answers and do rate me if u like it...!!!! Problem A B C D Which is thestrongest acid Which is theweakest acid 1 ABCD ABCD   2 ABCD ABCD   3 ABCD ABCD  

Manasi

Forum Expert

Posted on 10 Mar 2007 17:27:27 IST

Topic : Pinacol Rearrangement

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5

1454

Engineering Entrance , JEE Main

Pinacol itself is produced by magnesium reduction of acetone, probably by way of a ketyl intermediate. Since the diol is symmetrical, protonation and loss of water takes place with equal probability at either hydroxyl group. The resulting 3º-carbocation is relatively stable, and has been shown to return to pinacol by reaction in the presence of isotopically labeled water. A 1,2-methyl shift generates an even more stable carbocation in which the charge is delocalized by heteroatom resonance. Indeed, this new cation is simply the conjugate acid of the ketone pinacolone, which is the product of repeated rearrangements catalyzed by proton transfer. Each step in thi

Dinesh Babu

Blazing goIITian

Posted on 12 May 2007 21:47:05 IST

Topic : Aroma...!! ticity..! test take it..!

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7

680

Engineering Entrance , JEE Main

Choose the aromatic compounds from the following::

Saurav Agarwal

Blazing goIITian

Posted on 13 May 2007 14:52:16 IST

Topic : How to Study Organic Chemistry

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1

579

Engineering Entrance , JEE Main

Organic Chemistry is a challenging subject. It uses its own language and employs many very precise concepts yet without referring mathematical tools or aspects. Within first few hours of study you will be able to use the basic concepts to understand a lot about the molecular world around you.The first difficulty a student encounters is the amount of study material available about organic molecules and their reactions any standard text book is not less then 1400 pages long, a student cannot expect to learn all this material without investing a considerable time and effort in studying it and if he does so he disproportionates his time allocations with other subjects e

krishandeep sandhe

Hot goIITian

Posted on 11 May 2007 13:24:23 IST

Topic : cannizzaro reaction

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1

595

Engineering Entrance , JEE Main

CannizzaroDisproportionation of aromatic aldehydes into aromatic acids and aromatic alcohols.     The speed of the reaction depends on the substituents in the aromatic ring.     Crossing reaction (reaction of Rodionov and Fedorova) - using two different aldehydes (aromatic and aliphatic). Usually, fomaldehyde and alcohol are produced.     Intramolecular rearrangment reaction (also known as Cannizzaro's rearrangment) - transformation of alpha-ketoaldehydes into alpha-oxyacids.  

amit singh

Blazing goIITian

Posted on 11 May 2007 23:31:53 IST

Topic : Some important compounds

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8

880

Engineering Entrance , JEE Main

Important compounds and their formulae.   Alum -  (NH4)2SO4.Al2(SO4)3.24H2O Aqua fortis ? HNO3 Aquaregia ?Conc.HNO3 + conc. HCl (1:3) Asbestos ? CaMg3 (SiO3) 4 Baking soda or powder ? NaHCO3 Black lead - graphite Blue vitriol ? CuSO4.5H2O Baryta water ? Ba(OH) 2 SOLUTION Bremstone ? S8 Baryta - BaO Bleaching powder ? CaOCl2 Boranes ? Hydride of boron Calomel ? Hg2Cl2 Carbolic acid ? C6H5OH Carborundum - SiC Caro?s acid ? H2SO5 Caustic potash  - KOH Chromyl chloride ? CrO2Cl2 Corundum ? Al2O3 Coinage metals ? Cu, Ag and  Au Corrosive subli

krishandeep sandhe

Hot goIITian

Posted on 10 May 2007 03:09:59 IST

Topic : 13C-NMR

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1

531

Engineering Entrance , JEE Main

Carbon Nuclear Magnetic Resonance (13C-NMR) SpectroscopyNuclear Magnetic Resonance (NMR) Spectroscopy is not limited to the study of protons. Any element with a nuclear spin (13C, 17O, 19F, 31P and many others) will give rise to an NMR signal.Carbon-13 has a nuclear spin (I = ½) and makes up 1.1% of all naturally occurring carbon, a high enough abundance along with modern technology to make carbon nuclear magnetic resonance spectroscopy (13C-NMR) a useful technique. Since carbon is the element central to organic chemistry, 13C-NMR plays an important role in determining the structure of unknown organic molecules and the study of organic reactions and processes

krishandeep sandhe

Hot goIITian

Posted on 11 May 2007 14:38:07 IST

Topic : Arndt - Eistert rxn complete mechanism

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2

636

Engineering Entrance , JEE Main

MechanismIn the first step, the diazomethane carbon adds to the acid halide, to give an ?-diazoketone. In the second step, treatment with water or silver salt initiates a rearrangement with the R-group migrating to produce an isocyanate, which readily hydrolyses to give a carboxylic acid. If alcohols or amines are used instead of water, esters and amides are obtained, respectively.This rearrangement is known as Wolff rearrangement.

krishandeep sandhe

Hot goIITian

Posted on 10 May 2007 05:25:11 IST

Topic : interconversion of fung gps organic

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6

775

Engineering Entrance , JEE Main

 click to open itvery usefull  plz rate

krishandeep sandhe

Hot goIITian

Posted on 11 May 2007 13:28:44 IST

Topic : Arndt-Eistert rxn

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0

614

Engineering Entrance , JEE Main

Arndt-EistertSynthesis of higher homologues of carboxylic acids by interaction of diazomethane and acyl chlorides.       Newman-Beal modification - with triethylamine (which binds the HCl) and silver benzencarboxylate. Wilds modification - with higher alcohols; catalysts are not necessary.

krishandeep sandhe

Hot goIITian

Posted on 10 May 2007 21:31:32 IST

Topic : test- The Study of Chemical Reactions

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0

833

Engineering Entrance , JEE Main

1 .       Which equation correctly expresses the Gibbs free energy of a reaction as a function of the equilibrium constant Keq for the reaction?   G = ?RTln(K)   G = ?RTln(K)   G = ?RTlog(K)   G = +RTln(K)

Prashanth Sekhar

New kid on the Block

Posted on 4 May 2007 00:13:59 IST

Topic : Most wanted

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1

565

Engineering Entrance , JEE Main

Here are various lists...List of Organic reactions>>>LIst of organic compounds >>>List of inorganic compounds >>>List of biomolecules >>>List of minerals >>>List of alchemical substances >>>List of alloys >>>List of compounds >>>List of drugs >>>List of elements >>>List of proteins >>>Protective groups >>>List of named reagents with info >>>List of named reactions with info >>>Source : Wikipedia.org, Organic-Chemistry.com--------------------------------.:: Prashanth Sekhar ::.*******************(¨`?.?´¨) Always`?.¸

ishan maheshwari

Hot goIITian

Posted on 4 May 2007 12:38:22 IST

Topic : KNOWLEDGE FOR YOU

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2

461

Engineering Entrance , JEE Main

Vitamins, their sources & Diseases caused due To their deficiencies Vitamins, Their Sources And Diseases Caused Due To Their Deficiencies Name of the vitamin Main source Disease caused due to their deficiencies Vitamin A

amit singh

Blazing goIITian

Posted on 3 May 2007 04:36:46 IST

Topic : 3-D, animations

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569

Engineering Entrance , JEE Main

                    

goutham harsha (1nkZ)

Blazing goIITian

Posted on 26 Apr 2007 19:03:20 IST

Topic : hmmmm.......these will b useful :)

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1

1128

Engineering Entrance , JEE Main

silver carbonate and oxy salts of silver on heating strongly gives silver metal, same is the case with mercury also.1)      Carbonates of alkali metals except Li2CO3 are stable towards heat.2)    Sulphites of lead, barium and strontium are insoluble in water, Calcium sulphite is partially soluble in water, most of the other sulphites are soluble in water.3)    In reactions that involve nascent oxygen, we don?t use HCl because it is highly susceptible to oxidation nd gives out Cl2 gas.4)    I2 soln is almost insoluble in water, there fore, the I2 soln used is iodine in alcohol.5)   

goutham harsha (1nkZ)

Blazing goIITian

Posted on 26 Apr 2007 22:22:29 IST

Topic : ooooooooo....da reaction road map !! :)

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5

1188

Engineering Entrance , JEE Main

The Reaction Roadmap

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