a scientist has 400ml of a 8% solution. how much water needs to be added to lower it to a 2% solution?

1200 ml of water needs to be added to lower it to a 2% solution.

Step-by-step explanation:

Given that,

A scientist has 400ml of a 8% solution.

you need to find how water is required to lower the 400 ml to 2% solution.

Let 'x' be the amount of water added to lower it 2% solution.

The formula is given by,

volume of the liquid * % of solution = volume of the new liquid * new %

This can be denoted in chemical relationship ⇒ c₁v₁=c₂v₂ where c is concentration and v is volume.

Now, to find the total volume of new liquid in ml:

400 ml = v₁

0.08 = c₁

0.02=c₂

v₂=?

400 * 0.08 = v₂ * 0.02

v₂=1600 ml

To find the x value:

Amount to be added = volume of new liquid - volume of liquid before.

⇒ x = 1600-400

⇒ x = 1200 ml

∴ 1200 ml of water needs to be added to lower it to a 2% solution.