There is 500 g of a 40% acid solution. How much water do you need to add to get a 25% acid solution?

Let’s find how many grams of acid are in 500 gr. solution.

500 * 0.4 = 200 gr.

According to the condition of the problem, 200 g of acid is a 25% solution, then the entire solution will be (100%) 800 g.

Let’s find the amount of water needed to add to the initially available solution.

800 – 500 = 300 gr.

Answer: It is necessary to add 300 gr. water