Question

George wishes to increase the percent of acid in 50 ml of a 15% acid solution to 25% acid, how much pure acid must be added?

Answer 1

6.667 mLs

Step-by-step explanation:

.-.

Answer 2

`\approx 6.667ml`

Step-by-step explanation:

Let
`x` be the quantity of pure acid that you must add, and
`y` the total quantity of acid in the solution final solution. Then when you add x to the solution the 25% of it will be
`y`:

`y=.25(50+x)`

And
`y` is also equal to 15% of the solution of 50ml plus
`x`.

`y=.15(50)+x`

Equalize these two equations to form a new without y and solve:

`.25(50+x)=.15(50)+x\\12.5+0.25x=7.5+x\\12.5-7.5=x-0.25x\\5=0.75x\\x=5/0.75\\x=6(2)/(3)\approx 6.667ml`