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According to the law of mass action, the quantitative effects of temperature, pressure, concentration, volume and other factors on the equilibrium of a chemical reaction can be studied. For the qualitative study of these factors on equilibrium, franchise science le chatelier introduced a generalized rule in 1884 called le chatelier’s Principle.

French chemist Henry Louis Le Chatelier,

According to this rule –

If a system in equilibrium is subjected to a charge of concentration, pressure, temperature, volume etc., the equilibrium shifts in the direction that tends to undo the effect of the change.

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Formaldehyde Tests

Formaldehyde gives all the normal tests of the aldehyde group. It gives pink color with schiff reagent, silver mirror with tollan reagent and red precipitate with fehling solution.

Specific testing of formaldehyde is as follows.

A drop of 0.5% aqueous resorcinol solution is found in 1 ml of dilute aqueous solution of formaldehyde. This mixture is slowly found in the surface of 5 ml of concentrated H2SO4. Carefully stir the test tube in such a way that both the surfaces are not lost. A ring of red violet is formed at the meeting of both surfaces.

Add 1 ml of…

Aldehydes and Ketones

  • CHO Group is called formyl group and -CO- Group is called carbonyl group.
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When the -CHO group is attached to a hydrogen or carbon atom, it is called an aldehyde group. And the related compound is called aldehyde.

Example: -CHO group in HCHO is associated with H, so it contains aldehyde group and it is an aldehyde. In CH3CHO, -CHO is associated with group C, so it also has an aldehyde group and is also an aldehyde. -CHO group is present in HCOOH but it is associated with O, so aldehyde group is not present in this compound.

Compounds in…

Toluene: benzaldehyde is obtained from oxidation of toluene by chromyl chloride CrO2Cl2. This reaction is called Etard’s Reaction.

C6H5CH3 + 2CrO2Cl2 → C6H5CH(OCrOHCl2)2 → C6H5CHO

Benzaldehyde is also obtained by oxidation of acidic solution of toluene’s manganese dioxide MnO₂. In the presence of vanadium pentoxide(V₂O₅) at 350°C, oxidation of toluene by air oxygen also yields benzaldehyde.

Benzenal chloride: benzenal chloride (C7H7Cl) gets benzaldehyde on heating with lead nitrate solution in the atmosphere of carbon dioxide gas.

2C6H5CH2Cl + Pb(NO3)2 → 2C6H5CHO + PbCl2 + 2HNO2

Preparation Method

To make benzaldehyde in the laboratory, take 10 grams of benzene chloride, 8 gram lead…

Aniline Preparation

Laboratory method: from tin and HCl reduction of nitrobenzene: in the laboratory, aniline is made by the reduction of nitrobenzene by tin and HCl.

Sn + 4HCl → SnCl4 + 4H

C6H5NO2 + 6H → C6H5NH2 + 2H2O

Industrial manufacturing: from ioran and HCl reduction of nitrobenzene: Anealin is made by reduction of nitrobenzene by moist iron shavings and HCl in commercial quantities.

Fe + 3HCl → FeCl3 + 3H

C6H5NO2 + 6H → C6H5NH2 + 2H2O

Chlorobenzene: Chlorobenzene gets aniline at high pressure with ammonia in the presence of Cu2O and when heated to about 250°C.

C6H5Cl + NH3…

Chlorobenzene formula and structure
Chlorobenzene formula and structure


Laboratory Method

Aniline: Benzenediazonium chloride is obtained by replicating aniline with a mixture of NaNO2 and HCl at 0–5°C. Chlorobenzene is obtained by heating benzenediazonium chloride in the presence of cupreous chloride and hydrochloric acid.

C6H5NH2 + NH2 + HCl → C6H5 — N = N — Cl + 2H2O

The first reaction is called diazotization reaction and the second reaction is called sandmeyer reaction.

Read more about diazotization reaction and sandmeyer reaction

C6H5 — N = N — Cl → C6H5Cl + N2

Industrial Method

Chlorobenzene is obtained by mixing a mixture of benzene vapors, hydrogen chloride gas and oxygen (oxygen) at 250°C…

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Benzene was first discovered by Michael Faraday in 1825. Faraday obtained benzene from a distillation of while fish oil. Hofmann obtained it in 1845 from the fractional distillation of bitumen. A few decades from now, bitumen(coil tar) was the major source of benzene. Now the major source of benzene is petroleum.

Benzene is the basic compound of the aromatic group. Most aromatic compounds are derivatives of benzene. All aromatic compounds have a cyclic structure like benzene or Toluene.

Benzene preparation

Laboratory method: sodium benzoate

In the laboratory, benzene is made by distillation of sodium benzoate and soda lime.

C6H5COONa + NaOH → C6H6 + Na2CO3


What is Aromatic Compounds?

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aromatic compounds

Such compounds have been obtained from natural sources such as resins, balsam and bitter almond oil, which contain special type of smell.

These compounds are called aromatic compounds due to their special type of smell. The word aromatic originated from the Greek aroma meaning aroma.

Read more about Aromatic Compounds

The study of these compounds revealed that the percentage of carbon atoms in them is higher than corresponding aliphatic compounds. It has been found that the simplest of these compounds is the derivative of benzene and most other compounds benzene.

Therefore, initially benzene and its derivatives are called aromatic compounds

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Toluene is an aromatic hydrocarbon. Toluene is a colourless liquid and water-insoluble liquid. It is smell like paint thinners. Toluene IUPAC systematic name is Methylbenzene. Toluene was first derived from reagent named Tolu Balsam. Hence it was named toluene.

Preparation of Toluene:

Benzene: toluene can be made from benzene by a Friedel–Crafts reaction.

C6H6 + CH3Cl → C6H5CH3 + HCl

Bromobenzene: Toluene is obtained when sodium is reacted with an analogous mixture of bromobenzene and bromomethane in ethereal solution.

C6H5Br + 2Na + BrCH3 → C6H5CH3 + 2NaBr

Similarly, toluene is also obtained by the action of chlorobenzene and methyl chloride from sodium…

The alkyl derivatives of ammonia are called amine. In other words, the compounds that are obtained when the hydrogen atoms in the ammonia molecule are replaced by an equal number of alkyl groups. They are called amine.

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They are divided into three classes based on the number of alkyl groups associated with the nitrogen atom in amines.

The primary amines have only one alkyl group attached to the nitrogen atom, the secondary amines have two alkyl groups attached to the nitrogen atom and the tertiary amines have three alkyl groups attached to the nitrogen atom.

Nomenclature of amines

In the simplest method, amine…

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