Question: MY QUESTION:
IF YOU HAVE 1 Litre OF A 70% ACID SOLUTION, AT WHAT RATIO DO YOU DILUTE IT WITH WATER TO ACHIEVE A 30% AND 50% ACID SOLUTION?
THANKS,
ALEX

Alex,

I'll work on the 50% solution for you and you can do the 30% solution.

You have 1 litre of a 70% acid solution so the solution contains 0.7 litres of acid. You want to add enough water so that the 0.7 litres of acid accounts for 50% of the solution. To say this algebraically I need a variable for the amount of water I add so let x be the number of litres of water I add. So now I have

1 + x litres of solution which contains 0.7 litres of acid.

Thus, if this 0.7 litres of acid is 50% of the solution then

0.7 = 0.5 (1 + x)

You can now solve this algebraically for x but if you look at this equation it says

0.7 is half of 1 + x

Hence 1 + x must be 1.4 and thus x = 0.4 litres.

Now you try the 30% solution.

Penny