In this question, we have a dilution situation, in which we have an amount of volume of a solution, and we are diluting it with more water, which will then cause the concentration of the substance to decrease.
We have 100 mL and 12% KCl, which for a better understanding we can read 12 grams of KCl
We are adding 200 mL:
100 mL = 12 % or grams
300 mL = x % or grams
100x = 0.04
x = 0.04/100
x = 4.0%, therefore the correct answer will be letter E
