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