Vinegar is an aqueous solution of acetic acid.

Question

Vinegar is an aqueous solution of acetic acid. By law, it must contain 4 g acetic acid (CH3CO2H 60.05g/mol) per 100 mL solution although it is commonly up to 8% acetic acid. If a 15.00 mL aliquot of vinegar required 5.28 mL of 0.10 M NaOH to reach the end point, is the sample legally vinegar? Show your calculations to support your answer.

Answer 1

CH3COOH + NaOH ==> CH3COONa + H2O

mmoles NaOH used = 5.28 ml x 0.1 mmol/ml = 0.528 mmoles

mmoles CH3COOH = 0.528 mmoles (1:1 mol ratio)

0.528 mmol/15 ml x 100 ml = 3.52 mmol CH3COOH/100 ml

3.52 mmol/100 ml x 60 mg/mmol x g/1000 mg = 0.2 g/100 ml

Not legally vinegar.