Use the concept of electronegativity to justify why the acid strengths of ethanedioic acid and ethanoic acid are different. (6 marks)

Stage 1: 1-2 marksFirstly, draw and explain the difference in structures between the two acids.
Stage 2: 3-4 marksThe unionised COOH groups in the ethanedioc acid contain two very electronegative oxygen atoms. Therefore has a negative inductive effect, which means it is pulling electrons away from other atoms.The CH3 group in ethanoic acid has a positive inductive, meaning it pushes electrons away.
Stage 3: 5-6 marksDue to the negative inductive effect in ethanedioic acid, the O-H bond is more polarised. This means the hydrogen ion is more easily lost. Therefore there is more dissociation, which means it is a stronger acid.