Page 36 - Big Ideas Year 10 sciPAD 2025

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36 SCIPAD - BIG IDEAS - BOOK 2
BASIS OF CHEMICAL REACTIONS
Neutralisation
A chemical reaction occurs when you mix together an acid and a base. The base cancels out
the effects of the acid. The reaction is called a neutralisation reaction because a neutral solution
is made if you add just the right amount of acid and base together.
Aim: To observe a neutralisation reaction.
Equipment: A test tube, test tube rack, 1 mol L-1 Na2CO3 (sodium carbonate), 1 mol L-1 HCl
(hydrochloric acid), dropper or dropper bottle, Universal indicator solution.
Method:
Observations: 




1. What colour is Universal indicator solution in Na2CO3? 
2. Is Na2CO3 an acid or an alkali? 
3. The products of this reaction are sodium chloride, carbon dioxide and water. Write a word
equation for this reaction.

4. Using your observations, what evidence was there to indicate that carbon dioxide was
produced? 
5. How did you know when complete neutralisation had occurred? 

6. Describe what you would observe if too much acid was added during step 2. 

7. You enter the laboratory to find a large puddle of an unknown liquid on your workbench.
You suspect it is an acid spill. Describe how you could test to determine if it is an acid and
outline how it could be made safe before wiping it up. 





Add approximately 1-2 mL of Na2CO3 and
place the test tube into the test tube rack.
Add 3-5 drops of Universal indicator solution.
Using a dropper bottle, add HCl drop by drop. Be
careful because adding even a small amount of extra
acid can mean you’ll miss the neutralisation point.
Universal
indicator
Na2CO3
solution
Dilute HCl
1 2
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