Question

A 1.475 g sample of KHC8H4O4 is dissolved in 25 mL of water and then titrated with a NaOH solution. The initial buret reading before the titration is 12.15 mL. When the endpoint of the titration is reached the buret reading is 32.85 mL. What is the concentration of the NaOH solution.

Answer 1

The concentration of the NaOH solution used to titrate 1.475 g of KHC8H4O4 is calculated by first determining the volume of NaOH used and then using the mole ratio from the balanced chemical equation. The concentration of the NaOH solution is found to be 0.3488 M.

Step-by-step explanation:

To find the concentration of the NaOH solution used to titrate the KHC8H4O4, we first need to calculate the volume of NaOH used. We subtract the initial buret reading from the final buret reading:

Volume NaOH used = Final buret reading - Initial buret reading
32.85 mL - 12.15 mL = 20.70 mL or 0.02070 L

The balanced chemical equation for the reaction between KHC8H4O4 (potassium hydrogen phthalate) and NaOH is:

KHC8H4O4 + NaOH → KNaC8H4O4 + H2O

From the equation, it's clear that the reaction has a 1:1 molar ratio. Since we know the mass of KHC8H4O4, we can calculate the moles of KHC8H4O4, which will be equal to the moles of NaOH:

Moles of KHC8H4O4 = 1.475 g / (204.22 g/mol) = 0.00722 mol

Now we know the moles of NaOH and the volume it occupied, we can calculate the molar concentration of the NaOH solution:

NaOH concentration = Moles of NaOH / Volume of NaOH solution in liters

0.00722 mol / 0.02070 L = 0.3488 M