Question

A laboratory technician needs to make a 135​-liter batch of a 20​% acid solution. How can the laboratory technician combine a batch of an acid solution that is pure acid with another that is 10​% to get the desired​ concentration?

Answer 1

Answer:

15 liters of pure acid and 120 liters of 10% solution are needed.

Step-by-step explanation:

Let us assume that,

x = liters of pure acid ,

y = liters of 10​% acid.

As we need a total of 135 liter of batch, so

$x+y=135$  ------------------------------1

As we need to make a batch of 20​% acid solution, hence acid content of the mixture of two acids will be same as of the final one, so

$x+0.1y=135\times 0.2=27$  -----------2

Subtracting equation 2 for 1,

$\Rightarrow x+y-x-0.1y=135-27$

$\Rightarrow y-0.1y=108$

$\Rightarrow 0.9y=108$

$\Rightarrow y=120$

Putting this in the equation 1,

$\Rightarrow x+120=135$

$\Rightarrow x=135-120=15$

Therefore, 15 liters of pure acid and 120 liters of 10% solution are needed.