A total of 30.6 g of potassium hydrogen phthalate is needed to completely neutralize a 500.0 mL solution of sodium hydroxide. What is the molarity of the sodium hydroxide solution?

To find the molarity of the sodium hydroxide solution, we need to use the equation:

Molarity (M) = moles of solute / volume of solution (in liters)

First, we need to find the moles of potassium hydrogen phthalate (KHP) used for neutralization. We can use its molar mass to do this.

The molar mass of potassium hydrogen phthalate (KHP) is 204.23 g/mol.

Given that 30.6 g of KHP was used, we can calculate the moles using the formula:

moles = mass / molar mass

moles of KHP = 30.6 g / 204.23 g/mol = 0.1497 mol

Now, we need to determine the volume of the sodium hydroxide solution in liters.

Given that the volume is 500.0 mL, we must convert it to liters by dividing by 1000.

Volume of solution = 500.0 mL / 1000 = 0.500 L

Now that we have both the moles of KHP and the volume of the solution, we can calculate the molarity of the sodium hydroxide solution.

Molarity = moles of solute / volume of solution

Molarity = 0.1497 mol / 0.500 L = 0.2994 M

Therefore, the molarity of the sodium hydroxide solution is 0.2994 M.