Question

If 1.098 g of potassium hydrogen phthalate (KHP) with a molar mass of 204.22 g/mol required 20.76 mL of a sodium hydroxide (NaOH) solution for complete neutralization, what is the molarity of the sodium hydroxide solution? Provide a step-by-step explanation of the calculations involved in determining the molarity, considering the balanced chemical equation for the reaction and the stoichiometry of the neutralization process.

Answer 1

To find the molarity of the NaOH solution, calculate the number of moles of KHP that reacted, establish the mole-to-mole relation using the balanced reaction equation, and divide the moles of NaOH by its volume in liters, resulting in a molarity of 0.2588 M.

Step-by-step explanation:

To determine the molarity of the sodium hydroxide (NaOH) solution used to neutralize 1.098 g of potassium hydrogen phthalate (KHP), we follow these steps:

1. First, calculate the number of moles of KHP that reacted. The molar mass of KHP is 204.22 g/mol, so the number of moles is given by the mass of KHP divided by its molar mass.
2. Using the balanced equation for the reaction, which is KHP + NaOH → salt + H2O, we can see it's a 1:1 ratio, meaning the number of moles of NaOH that reacted is equal to the number of moles of KHP.
3. Lastly, to find the molarity of the NaOH solution, divide the number of moles of NaOH by the volume of the NaOH solution in liters. The volume in the problem is given in milliliters, so it must be converted to liters before using it in the calculation.

Thus, the molarity is calculated as follows:

1. Number of moles of KHP: (1.098 g) / (204.22 g/mol) = 0.005374 moles.
2. Molarity of NaOH = Number of moles / Volume (L), which is 0.005374 moles / 0.02076 L = 0.2588 M.