Complete the following reaction: Ar - NH 2 → ? Ar - N 2 ⊕ Cl ⊝ → Cupprous chloride HCl ?

Aromatic primary amines react with nitrous acid to form diazonium salt. The chemical reaction is as follows: Benzene diazonium chloride reacts with cuprous chloride and hydrochloric acid to form chloro -benzene chloride and nitrogen, this reaction is known as the Sandmeyer reaction. The complete chemical reaction is as follows: Ar - NH 2 → NaNO 2 + HCl HNO 2 Ar - N 2 ⊕ Cl ⊝ → Cupprous chloride HCl Ar - Cl + N 2 .

Complete the following reaction: Ar - N 2 ⊕ Cl ⊝ → H 3 PO 2 ?

Benzene diazonium chloride when reacts with hypophosphorous acid which is a reducing agent the salt reduced to produce benzene. The complete chemical reaction is as follows: Ar - N 2 Cl + H 3 PO 2 + H 2 O ⟶ Ar — H + H 3 PO 3 + HCl + N 2 The diazonium is replaced by a hydrogen atom, that is, benzene would be formed. H 3 PO 2 gets oxidised H 3 PO 3 and Benzene diazonium chloride gets reduced to benzene.

Explain carbylamine reaction with an example.

Carbylamine reaction mechanism includes the addition of amine to the intermediate created from the dehydrohalogenation of chloroform. This intermediate is called dichlorocarbene. The carbylamine reaction is also known as Hofmann isocyanide synthesis. It is the reaction of a primary amine, chloroform and a base to synthesize isocyanides. The dichlorocarbene intermediate is very important for this conversion. The carbylamine reaction cannot be used to synthesize isocyanides from secondary or tertiary amines. In general, the carbylamine reaction can be written as follows, R - NH 2 + CHCl 3 + 3 KOH → RNC ( Carbylamine ) + 3 KCl + 3 H 2 O .

Write short notes on Coupling reaction.

The azo products obtained have an extended conjugate system having both the aromatic rings joined through the – N = N – bond. These compounds are often coloured and are used as dyes. Benzene diazonium chloride reacts with phenol in which the phenol molecule at its para position is coupled with the diazonium salt to form p - hydroxyazobenzene. This type of reaction is known as coupling reaction.