what is diazonium salt??explain?
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Answer:
What are Diazonium Salts?
The diazonium salts of diazonium compounds are the class of organic compounds with general formula R−N2+X−. Here, X is an organic or inorganic anion (for example, Cl–, Br–, BF4–, etc.) and R is an alkyl or aryl group. The term is derived from two words. ‘di’ refers to ‘two’, azo is indicative of ‘nitrogen’ and item implies that it is cationic in nature.
Diazonium salts
Hence, they have two nitrogen atoms with one being charged. Benzenediazonium chloride (C6H5N2+Cl–), benzene diazonium hydrogen sulfate (C6H5N2+HSO4–), etc. are some of the examples of the diazonium salt.
Now, we look at the properties of diazonium salts. You can learn them as they are important from the exam point of view.
Browse more Topics under Amines
Chemical Reactions of Amines
Classification of Amines
Nomenclature of Amines
Physical Properties of Amines
Preparation of Amines
Properties of Diazonium Salts
They are ionic in nature.
They are water-soluble.
Aryl diazonium salts are colorless crystalline solids.
Benzenediazonium chloride is soluble in water. But, it reacts with it only when warmed.
Benzenediazonium fluoroborate is not soluble in water. It is pretty stable at room temperature. So, where do we use these salts? Do you know about its applications? Let us see below.
Importance of Diazonium Salts
We use diazonium salts in the dye and pigment industries. They play a major role to produce dyed fabrics.
You can use them in document reproduction. This is because they have a property of breaking down in ultraviolet light.
They are useful in the synthesis of a large variety of organic compounds, especially aryl derivatives.
Direct halogenation is not a suitable method for preparing aryl iodides and fluorides. Nucleophilic substitution of chlorine in chlorobenzene by a cyano group is not possible. However, we can use diazonium salts to produce cyanobenzene easily.
It is not possible to prepare substituted aromatic compounds by direct substitution in benzene. For these compounds, we use the replacement of the diazo group in diazonium salts.
They are essential as intermediates for introducing –F, –Br, –Cl, –I, –NO2, –OH and –CN groups into the aromatic ring.
Solved Example For You
Q: Write down the method for the preparation of diazonium salts.
Ans: Diazotization or dissociation is the process of converting an organic compound, generally primary aromatic amines into diazonium salts. Diazonium groups are very unstable and therefore, we can’t store them. Thus, we normally use them immediately after preparation. One of the most common methods of preparation of diazonium salt is by the reaction of nitrous acid with aromatic amines.
The reaction of aniline (aromatic amine) with nitrous acid results in the formation of the diazonium salt. This salt is the benzene diazonium chloride. Nitrous acid is a highly toxic gas. Therefore, it is generally prepared during the reaction itself by reacting NaNO2 with a mineral acid.