10 cm of 2 mol/dm hydrochloric acid is diluted with water to a total volume of 100 cm. What is the new concentration?
Answer and explanation
Correct answer: B. 0.2 mol/dm
- Step 1: The amount of acid is unchanged: .
- Step 2: mol/dm.
Answer
0.2 mol/dm.
Why not the others: 20 mol/dm: it inverts the volume ratio. 0.02 mol/dm: it ignores the original volume. 1.8 mol/dm: it uses the volume of water added instead of the original volume.
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