Q. How does benzene undergo nitration?
Benzene reacts with concentrated nitric acid at temperature of 50 to 60 degrees Celsius with a concentrated sulfuric acid catalyst to from nitrobenzene and water. Sulfuric acid is regenerated when the hydrogen sulfate ion reacts with the proton that is expelled from the intermediate.
Q. How is the side chain of methylbenzene completely oxidised to give benzoic acid?
Alkyl groups attached to a benzene ring are oxidised fairly easily when heated under reflux with alkaline potassium permanganate solution. Dilute sulfuric acid is then added to produce benzoic acid. Purple solution --> Dark brown precipitate of manganese dioxide.
Q. How does the ring of delocalisation affect the reactions of benzene?
The electron density in benzene is relatively low, resulting in a weak attraction to electrophiles. As a consequence, benzene cannot undergo electrophilic addition reactions and instead slowly participates in electrophilic substitution reactions. If benzene were to undergo addition reactions, it would permanently disrupt the delocalization of electrons, which is energetically unfavorable for this type of reaction.
Q. What is a directing effect?
Substituents on a benzene ring can affect at which position a further substitution reaction might occur on.
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