Question

A titration of 25.00ml of 0.1550 M HCl solution with a solution of NaOH of unknown molarity starts at a buret reading for NaOH of 0.33 ml. The phenolphthalein indicator turns light pink in the acid solution for over 30 seconds at a buret reading of 24.19 ml. What is the molarity of the NaOH solution?

Answer 1

To determine the molarity of the NaOH solution, the formula M1V1 = M2V2 can be used. The molarity of the NaOH solution is found to be 8.90 M.

Step-by-step explanation:

To determine the molarity of the NaOH solution, we can use the equation:

M1V1 = M2V2

where M1 is the molarity of HCl, V1 is the volume of HCl used for titration, M2 is the molarity of NaOH, and V2 is the volume of NaOH used for titration. In this case, the volume of HCl used is (24.19 mL - 0.33 mL) = 23.86 mL, and the volume of NaOH used is 0.33 mL. The molarity of HCl is 0.1550 M. Plugging these values into the equation:

(0.1550 M)(23.86 mL) = (M2)(0.33 mL)

Solving for M2:

M2 = (0.1550 M)(23.86 mL) / (0.33 mL) = 8.90 M

Therefore, the molarity of the NaOH solution is 8.90 M.