Messages posted by Madhusudan Chavan

.:- 1,2-diols, known as pinacols, also undergo a similar type of dehydration reaction when treated with acid to furnish a ketone or aldehyde which have rearranged structure

compared to the initial diol. This transformation is commonly referred to as Pinacol

Rearrangement. Let’s take an example – when pinacol reacts with an acid, it leads to the

formation of pincolone. It is believed that this reaction also involves the formation of a

tertiary carbocation in the first step which is followed by 1,2-shift of the methyl group.

Now, the question will be if we already have a stable carbocation, why should it undergo

rearrangement? The answer is - the oxygen lone pair - which can stabilize the newly

formed carbocation by donating its lone pair to carbocation, thereby completing octet for

all the atoms involved. In fact, one could view this reaction as a ‘push-pull’ reaction! The

carbocation ‘pulls’ the alkyl group along with its bonding electrons towards itself while

the oxygen lone pair ‘pushes’ the alkyl group away.

Electronegativity of fluorine is more than that of chlorine hence fluoroform should be more acidic than chloroform.

Furanose from furan a five membered ring.

Pyranose from pyran a six membered ring

Glycine-alanine-Phenylalanine; Alanine-Glycine-Phenylalanine; Phenylalanine-Glycine-alanine; Glycine-Phenylalanine-Alanine; Alanine-Phenylalanine-Glycine; Phenylalanine-Alanine-Glycine

The possibilities would be

Gly-Ala-Phala; Ala-Gly-Phala; Phala-Ala-Gly; Ala-Phala-Gly

Amides show resonance, but it should not restrict the free rotation in one of the contributing form , hence and (a) appears to be correct.

In Etard reaction ( oxidation with CrO2Cl2) toluene is oxidised to benzaldehyde. Toluene is the main substrate that has been studied. The oxidation of n-propyl benzene gives propiophenone and benzyl methyl ketone. The benzyl methyl ketone is obtained by rearrangement.

When more than one methyl group is present, only one is oxidised, e.g., m-xylene gives m-tolualdehyde.

From the above discussion, I hope it will be clear that oxidation occurs at the m-poistion also.

Urea NH2CONH2 exists as resonance hybrid where both nitrogens exists as NH2+ and oxygen as O-. The negatively charged oxygen is capable of co-ordinating with one proton , therefore usrea is called monoacidic base. The salt formed by accepting a proton also exists as resonance hybrid.

Carbene is actually produced from CHCl3

CHCl3 + OH .........> H2O + CCl3-

CCl3- ..........> :CCl2 + Cl-

CCl4 on reaction with OH ( KOH) gives K2CO3 via C(OH)4 , to CO2

It is Schotten-Baumann reaction.

They are functional isomers of esters, for ex. CH3COOH is isomeric with HCOOCH3; CH3CH2COOH & CH3COOCH3

I hope you are reffering to Lucas test ( With ZnCl2 & HCl). The order of reactivity of alcohol is tert. > sec.> prim. hence pprimary alcohols do not give turbidity immediately.

During Hoffmann's elimination a double bond is formed which may be endo or exocyclic

An interesting feature of double bonds is that they may be part of a ring system, in which case they are called endocyclic double bonds because their p bond lies “within” the ring. Double bonds may also project from a ring, in which case they are called exocyclic double bonds because their p bond lies “outside” the ring. If a compound is bicyclic, a double bond might be endocylic with respect to one ring and exocyclic with respect to the other ring.

Figure 2. Types of double bonds.

Figure 2 shows that a double bond is endocyclic if its p bond is part of the ring. Whereas, the double bond is exocyclic if its p bond projects from the ring. If a double bond is exocyclic to a ring, it adds 5 nm to the base wavelength of a conjugated diene.

Finar, or Bahl's Organic chemistry books give both common names and IUPAC names. Finar is excellant book for organic reactions

two electrons per pi bond, in case of heterocyclic five membered ring add two electrons of the hetero atom.

Organic chemistry is very easy and systematic chemistry. Love it, enjoy studying organic chemistry. Begin with NCERT books, throughly read and understand each topic, do self assessment by solving questions from each topic. Then go to higher books like Arihant/ MTG etc.

In chemistry, acid value (or "neutralization number" or "acid number" or "acidity") is the mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of chemical substance.

There is a long list of reagents, better refer to any standard book like MTG's reaction mechanism or Arawals reactions and reagents for the list.

For a compound to be optically active it should have chiral carbon, no symmetry.

I think Huckel number rule is for aromaticity and not for chirality.

Fehling's solution is copper tartarate complex which affords small conc. of Cu2+ ions. Probably benzaldehyde forms a complex with Cu2+ hence it does not reduce it.

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