A 2.58-g sample of NaOH(s) is added to enough water to make 600.0 mL of solution at 25°C. What is the pH of this solution?
A) 10.03
B) 0.97
C) 13.03
D) 14.63
E) 12.59

Question

Quizplus · Accepted Answer

The molarity of the NaOH solution is calculated by dividing the moles of NaOH by the volume of the solution in liters. The moles of NaOH are found by dividing the mass (2.58 g) by the molar mass of NaOH (approximately 40 g/mol), giving 0.0645 moles. The volume of the solution is 0.6 L, so the molarity is 0.1075 M. Since NaOH is a strong base, it fully dissociates, and the concentration of OH- is 0.1075 M. The pOH is -log(0.1075) = 0.968. The pH is 14 - pOH = 13.03.

A 258-G Sample of NaOH(s) Is Added to Enough Water to to Make