Question IT! Acids & Alkalis
10 MARKS
AfL
Target Grade (A)
Hydrogen carbonate indicator solution
changes colour when the amount of
carbon dioxide gas dissolved in it
changes.
Colour of Indicator Solution
Amount of Dissolved Carbon Dioxide
Same amount of carbon dioxide as in the air
Reddish-orange
Yellow
More carbon dioxide than in the air
Purple
Less carbon dioxide than in the air
This is shown in the Table opposite.
i.
Four test tubes were set up as shown opposite. Air was bubbled
through hydrogen carbonate indicator solution, which was then
poured into each test tube. The test tubes were then left in sunlight
for two hours.
Describe and explain the colour change of the indicator solution
in tube A. (3 marks)
ii. Describe and explain the colour change of the indicator solution
E
Contains
Contains
in tube B. (3 marks)
small snails waterweed
iii. The colour of the indicator solution in tube C did not change.
Explain why? (1 mark)
iv. Describe and explain the colour change of the indicator solution in tube D (3 marks)
с
Contains
small snails
and
waterweed
D
Contains
waterweed
(wrapped in
black paper)