What volume of distilled water must we add to 50 mL of a 20 % solution to get concentrations of 15 %, 10 % and 5 %?
1 Answer
Add 17 mL, 50 mL, and 150 mL of water, respectively.
Explanation:
We can use the dilution formulas for these calculations:
#color(blue)(bar(ul(|color(white)(a/a)c_1V_1 = c_2V_2color(white)(a/a)|)))" "#
We can rearrange this formula to get
#V_2 = V_1 × c_1/c_2#
15 % concentration
The final volume must be 67 mL, so you must add 17 mL of distilled water to get a 15 % solution.
10 %concentration
The final volume must be 100 mL, so you must add 50 mL of distilled water to get a 10 % solution.
5% concentration
The final volume must be 200 mL, so you must add 150 mL of distilled water to get a 5 % solution.