What is the molarity of an unknown NaOH solution if 50 mL of the solution is titrated to a phenolphthalein endpoint with 62.5 mL of 0.102 M HCl? This question requires the sudent to write a balanced equation for the reaction to determine the reacting mole ratio. The student will use the appropriate formula to determine the moles of HCl in 62.5 mL of 0.102M HCl and use the ratio to determine moles of NaOH contained in 50mL of the unknown. Finally, the student will deterine the moles of NaOH contained in 1000mL of the solution to get the Molarity.