To calculate the percent acetic acid in the vinegar, we need to determine the number of moles of acetic acid present in the sample and then calculate its mass based on its molar mass. Finally, we can express this mass as a percentage of the original sample mass.

Step 1: Calculate moles of NaOH used in the titration

Moles of NaOH = Concentration of NaOH × Volume of NaOH used

Moles of NaOH = 0.108 M × 31.43 mL / 1000 mL/L

Moles of NaOH = 0.0033846 moles

Step 2: Determine moles of acetic acid

Since the reaction between NaOH and acetic acid is a 1:1 stoichiometry, the moles of acetic acid are equal to the moles of NaOH used in the titration.

Moles of acetic acid = 0.0033846 moles

Step 3: Calculate mass of acetic acid

Molar mass of acetic acid (CH3COOH) = 60.05 g/mol

Mass of acetic acid = Moles of acetic acid × Molar mass of acetic acid

Mass of acetic acid = 0.0033846 moles × 60.05 g/mol

Mass of acetic acid = 0.2031 grams

Step 4: Calculate percentage of acetic acid in vinegar

Percentage of acetic acid = (Mass of acetic acid / Mass of vinegar) × 100%

Percentage of acetic acid = (0.2031 g / 4.441 g) × 100%

Percentage of acetic acid = 4.572 %

Therefore, the vinegar sample contains 4.572% acetic acid.