Both diagrams, 1 and 2, have HCl, the Strong Acid (SA).
Diagram 1
- In diagram 1, there is a lot of the strong acid SA, and less water.
- Thus we say it is concentrated.
- This also makes it very dangerous
- In diagram 2, there is very little of the strong acid SA, and more water.
- Thus we say it is dilute.
- This makes it harmless, even though it is still the strong acid SA.
Adding water to a strong acid does NOT make it weak.
Adding water only makes it dilute.
It is still strong, but now harmless.
The word "strong" refers to it's ability to react. The acid is still strong if there was a lot of it, or a little.