How many litres of a 50 percent acetic acid solution must be added to

Question

How many litres of a 50 percent acetic acid solution must be added to 12 litres of water to create a 20% acetic acid solution ?

A) 1
B) 2
C) 3
D) 6
E) 8

ishwan · Answer

Ans : E (8 ounces)

0.5x + 0(y) = 0.2 (x+y)

0.5x --> 50% acetic acid solution  
0(y) ---> 12 litres water --which mean 0% acetic acid
0.2 (x+y) ---> 20% resulting solution

Solving we get ,
0.3x = 0.2y

We know that y is 12 litres, substitute y value

x= 8

dave13 · Answer

\frac{12+0.5L}{12+L}=\frac{8}{10} L = 8 E

D33T · Answer

How many litres of a 50 percent acetic acid solution must be added to 12 litres of water to create a 20% acetic acid solution ?

Solution 1 = 50% acetic acid
Solution 2 = 20% acetic acid 
--> Let A = vol. of Solution 1 to be added

Applying the formula C1V1 = C2V2: 
50% x A = 20% x (A+12) 
50A = 20A + 240
30A = 240
A = 8

Ans: D) 6

yannichc · Answer

can use alligation here -

A/B= (0-20)/(50-20)

A/B= 2/3

2/3*12 = 24/3 = 8

SubaitaS · Answer

Why would we do 2/3 and not 2/5 in the last line, could you ple explain that, I'm stuck right there 😭

Bunuel · Answer

Let x be the number of liters of 50% solution added.

Then pure acid added = 0.5x
Total volume = 12 + x

We want 20% acid in the final mixture, so:

0.5x/(12 + x) = 0.2
x = 8

Answer: E.

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