Read the investigation carefully and answer the following questions:
A science teacher gave four colourless solutions labelled A, B, C and D. The students were told that some were acids, some were bases, and one was neutral.
The students performed the following tests.
| Solution | Red Litmus | Blue Litmus |
| A | No change | Turns red |
| B | Turns blue | No change |
| C | No change | No change |
| D | Turns blue | No change |
The students then mixed:
- Solution A with Solution B.
- Solution A with Solution D.
They observed that heat was produced during both reactions.
Finally, the teacher explained that whenever an acid reacts with a base, neutralisation occurs, producing salt and water.
Answer variants:
remain basic
will
Salt + Water + Heat
a base reacts with a base
an acid reacts with a base
will not
Water + Heat
Base
Neutralisation Reaction
Neutral
Acid
Addition Reaction
1. Identify the nature of Solutions A, B, C and D.
Solutions A -
Solutions B -
Solutions C -
Solutions D -
2. Draw a flowchart showing the sequence of events when Solution A reacts with Solution B.
Solution A + Solution B
⇓
⇓
⇓
The Solution Becomes Neutral
3. One student accidentally mixed Solution B with Solution D instead of Solution A. Predict whether a neutralisation reaction would occur. Explain your answer using the observations given.
Solution B turns red litmus paper blue, indicating that it is a base.
Solution D also turns red litmus paper blue, showing that it is a base.
Neutralisation occurs only when . Since both Solution B and Solution D are bases, there is no acid present to react with the bases.
Therefore, neutralisation take place, and salt and water be formed. The mixture will in nature.