Question

How many ml of 2.50 M NaOH solution are required to make a 525 mL of 0.150 M?

Answer 1

The correct answer is 31.5 ml

Step-by-step explanation:

We have to dilute the more concentrated solution (2.50 M) to obtain a solution with a molarity of 0.150 M. We have the following data:

Initial concentration = Ci = 2.50 M

Final concentration = Cf = 0.150 M

Final volume = Vf = 525 ml

We consider the final and initial states and use the following expression to calculate the initial volume (Vi) in ml:

Ci x Vi = Cf x Vf

Vi= (Cf x Vf)/Ci = (0.150 M X 525 ml)/2.50 M = 31.5 ml

Answer 2

31.5 mL of a 2.50M NaOH solution

Step-by-step explanation:

Molarity (M) is an unit of concentration defined as moles of solute (In this case, NaOH), per liter of solvent. That is:

Molarity = moles solute / Liter solvent

If you want to make 525mL (0.525L) of a 0.150M of NaOH, you need:

0.525L × (0.150mol / L) = 0.07875 moles of NaOH

If you want to obtain these moles from a 2.50M NaOH solution:

0.07875mol NaOH × (1L / 2.50M) = 0.0315L = 31.5 mL of a 2.50M NaOH solution