CAIE A Level Chemistry 9701 · Hydrocarbons
A student carries out the nitration of benzene using a mixture of concentrated nitric acid and concentrated sulfuric acid at 50 °C. Explain why substitution occurs instead of addition, and describe the role of the concentrated sulfuric acid in the formation of the electrophile.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.