What is the purpose of the hydrochloric acid solution during the formation of the diazonium salt?
The key purpose of HCl is to further convert HNO2 into the powerful electrophile NO+, the “nitrosonium ion“, which is the key electrophile in the reaction that forms the diazonium salt.
What is the method for preparation of diazonium salt?
One of the most common methods of preparation of diazonium salt is by reacting nitrous acid with aromatic amines. The reaction of aniline (aromatic amine) with nitrous acid results in the diazonium salt formation that is benzene diazonium chloride.
Why nano2 is used in diazotization reaction?
HCl converts NaNO 2 to HNO 2 further converting it into nitrosonium ion (NO + ) which is a strong electrophile. This electrophile is responsible for the formation of a diazonium salt. The formation of nitrosonium ion takes place by protonation of a hydroxyl group (OH – ) resulting in loss of a water molecule.
What is the purpose of using hydrochloric acid HCl in the diazotization step?
1 Answer. Explanation; Excess of HCl is used to convert free aniline to aniline hydrochloride otherwise free aniline would undergo coupling reaction with benzenediazonium chloride.
What is diazonium salt explain its stability?
Due to resonance there is a dispersal of positive charge on the benzene ring. This resonance accounts for the stability of the diazonium ion. Hence, diazonium salts of aromatic amines are more stable than those of aliphatic amines.
Which type of indicator is used in diazotization titration?
starch iodide paper
After the solution has been slowly titrated with sodium nitrite solution, starch iodide paper is used as an indicator to evaluate the titration.
What is the principle involved in diazotization method?
PRINCIPLE. The principle involved in this method is that the primary aromatic amine present in the sample reacts with the sodium nitrite in the presence of acid such as hydrochloric acid to obtain a diazonium salt.
Why diazonium salts are highly reactive?
Diazonium salts in general are high energy materials that can decompose violently either by heating or by mechanical force (shock-sensitive), so in that sense, they may be considered self-reactive. A reaction enthalpy of -160 kJ/mol to -180 kJ/mol is associated with the diazo functional group.
What is principle of diazotization titration?
What indicator is used in diazotization titration?
What is coupling reaction Why is Diazotisation reaction carried out at low temperature?
We have to maintain a low temperature during diazotization and coupling reactions because diazonium salts form other materials at high temperature and provide phenol by reacting at high temperature with water, which will lead to a major mistake in the experiments.
Why HCl is used in Diazotisation?
Excess of hydrochloric acid avoids the possibility of coupling reaction by leaving no free aniline for coupling reaction.