CAIE A Level Chemistry 9701 · Carboxylic acids and derivatives
A student adds a small piece of magnesium ribbon to a test-tube containing ethanoic acid. Effervescence is observed and the magnesium disappears. Explain, in terms of the reactions of carboxylic acids, what happens in this reaction and how the products could be identified.
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.