Question

I have 20%solution ofH2So4,100litres.
I want 40%solution of 200lit.
How many liter mix solution ofH2So4 of 98%

Answer 1

You want a 40 percent solution. Now you have two sulfuric acids:
100L of 20 percent
and X liters of 98 percent sulfuric acid.

I am wondering which sulfuric acid you want to use to make the 40 percent solution.

in the 100l, you have 20 liters of sulfuric acid. You will need a total of 40 liters of acid to make the 40 percent solution.

Start with 100 L of the 20 percent. Then add 20/.98 L of the concentrated 98 percent stock. Then the remaining volume is water. Because you have to add acid to water, first measure the water: 200-100-20/.98 liters water.
then add the acid solution to the water, stiring.