CAIE A Level Chemistry 9701 · Carboxylic acids and derivatives
A student warms a sample of ethanedioic acid, , with an excess of warm acidified solution. The purple colour of the fades and a colourless gas is given off. Describe what is observed and identify the gas. Write an equation for the reaction.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.