Question

Pure acid is to be added to a 5% acid solution to obtain 95L of 28% solution. What amounts of each should be used? How many liters of 100% pure acid should be used to make the solution?

Answer 1

We know that

• Pure acid is added to a 5% acid solution.

,

• To obtain 95 liters of 28% solution.

Based on the given information, we can define the following formula

`x+0.05(95-x)=0.28\cdot95`

Where 0.05 is 5% and 0.28 is 28%.

Solving for x, we have

`\begin{gathered} x+4.75-0.05x=26.6 \\ 0.95x=26.6-4.75 \\ 0.95x=21.85 \\ x=(21.85)/(0.95)=23 \end{gathered}`

This means there will be 23 liters of pure acid to 72 liters of 5% solution. (23 + 72 = 95 liters in total).

Now, to find the liters of 100% pure acid, we use the following equation.

`23+0.05\cdot72=0.28\cdot95=26.6`

Therefore, 26.6 liters of acid is needed.