Question

If there are 100 mL of a 6.0 M solution of NaOH but a 5.0 M solution is needed, how much water should be added to the 6.0 M solution to make in 5.0 M?

Answer 1

use dilution formula

M1*V1 = M2*V2

Here:

M1 is molarity of solution before dilution

M2 is molarity of solution after dilution

V1 is volume of solution before dilution

V2 is volume of solution after dilution

we have:

M1 = 6.0 M

M2 = 5.0 M

V1 = 100.0 mL

we have below equation to be used:

M1*V1 = M2*V2

V2 = (M1 * V1) / M2

V2 = (6*100)/5

V2 = 120 mL

This is final volume of solution

Difference in volume is due to added water

amount of water = 120 mL - 100 mL = 20 mL

Answer: 20 mL