A chemistry laboratory requests a 25% solution of ferrous sulphate. A supplier has 40 millilitres of a 20% solution. How many millilitres of 40% solution should be added to make it a 25% solution (correct to two decimal places)?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 13.33.
Let x be the volume of a 40% solution of ferrous sulphate
= 3 : 1
3 units = 40 ml
1 unit = 40/3 = 13.33 ml
Thus, x = 13.33