How many liters of water must be added to 8 liters of a 40% acid solution to obtain a 10% acid solution?
You would add 24 L of water.
We will assume that the density of the solution remains constant (even though the density changes with concentration!).
A 40 % concentration means
So the volume of acid in 8 L of solution is
So you have
You want to add
You would have to add 24 L of water.