How much water must be added to 1 liter of a 5% saline solution to get a 2% saline solution?

If 1 liter has 5% of saline solution, we know that our solution has 2,5 times the salt we want it to have: [tex]\frac{5\%}{2\%} =2.5[/tex], which means that, in the liter of water, there is an amount of salt that is 1,5 greater than what is desired.
Then, if we want to lower the concentration of salt, we just have to add water. How much water? 1.5 liters. Then, 5% of solution divided in 2.5 liters of water yields in a 2% solution.

anjalipriya1 anjalipriya1 · Answer 2 · 2019-11-27T12:21:19+01:00

Answer:

The water must be added to 1 liter of a 5% saline solution to get a 2% saline solution is 1.5 litres

Explanation:

We assume that the quantity of water added to be x litres. The quantity of saline in the existing solution is 5% of 1litre = 0.05 litres, with the addition of water, the quantity of new solution becomes (1 + x) litres. As per the problem, the percentage of saline in new solution should be equal to 2%. Therefore,

[tex]\frac{0.05}{1+x} \times 100=2[/tex]

So, 5 = 2(1+x)

2x = 5 - 2

[tex]x=\frac{3}{2}=1.5[/tex]

So, 1.5 litres water should be added to make the 1litre 5% saline solution a 2% saline solution.