Question

there are two solutions of Sulphuric Acid (acid + water) with concentration of Acid 50% and 80% respectively. They are mixed in a certain ratio to get a 62% sulphuric acid solution. This solution is mixed with 6 litres of water to get back 50% solution. How much of the 80% concentration solution has been used in the entire process​

Answer 1

Given:

• The initial concentrations of acid mixed are 50% and 80%.
• Final concentration of acid is 62%
• The concentration of acid becomes 50% after adding 6L of water to the 62% solution.

To find:

The volume of 80% sulfuric acid used.

Solution:

• Let the volume of 80% acid be x and the volume of 62% acid be v.
• The amount of sulfuric acid remains same before and after adding 6L water. So, 62v/100 = 50(v+6)/100 ⇒ v = 25L
• If x is the volume of 80% acid then the volume of 50% acid will be (25-x)
• Comparing the amount of sulfuric acid before and after mixing, we get 50(25-x)/100 + 80x/100 = 62×25/100 ⇒ x = 10L

Answer:

The volume of 80% sulfuric acid used is equal to 10L