Question

A 0.1873 g sample of a pure, solid acid, H2X (a diprotic acid) was dissolved in water and titrated with 0.1052 M NaOH solution. If the molar mass of H2X is 85.00 g/mol, calculate the volume of NaOH solution needed in the titration.

Answer 1

Answer:

We need 41.8 mL of NaOH

Explanation:

Step 1: Data given

Mass of H2X = 0.1873 grams

Molarity of NaOH solution = 0.1052 M

Molar mass of H2X = 85.00 g/mol

Step 2: The balanced equation

H2X (aq) +2 NaOH (aq) → Na2X (aq) + 2H2O(l)

Step 3: Calculate moles of H2X

Moles H2X = mass H2X / Molar mass H2X

Moles H2X = 0.1873 grams / 85.00 g/mol

Moles H2X = 0.0022 moles

Step 4: Calculate moles of NaOH

For 1 mol H2X we need 2 moles NaOH to produce 1 mole of Na2X and 2 moles of H2O

For 0.0022 moles of H2X we need 0.0044 moles of NaOH

Step 5: Calculate volume of NaOH

Volume of NaOH = moles of NaOH / molarity of NaOH

Volume of NaOH = 0.0044 moles / 0.1052 M

Volume NaOH =  0.0418 L = 41.8 mL

We need 41.8 mL of NaOH