Question

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

Answer 1

- 1,5 liters

Step-by-step explanation:

• If 1 liter has 5% of saline solution, we know that our solution has 2,5 times the salt we want it to have:
  `(5\%)/(2\%) =2.5`, 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.

Answer 2

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

Step-by-step 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,

`(0.05)/(1+x) * 100=2`

So, 5 = 2(1+x)

2x = 5 - 2

`x=(3)/(2)=1.5`

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