Maleic acid is a carbon–hydrogen–oxygen compound used in dyeing and finishing fabrics and as a preservative of oils and fats. In a combustion analysis, a 1.054 g sample of maleic acid yields 1.599 g CO₂ and 0.327 g H₂O. In a freezing-point depression experiment, a 0.615 g sample of maleic acid dissolved in 25.10 g of glacial acetic acid, CH₃COOH(l) (which has the freezing-point depression constant K_f = 3.90 °C m^-1 and in which maleic acid does not ionize), lowers the freezing point by 0.82 °C. In a titration experiment, a 0.4250 g sample of maleic acid is dissolved in water and requires 34.03 mL of 0.2152 M KOH for its complete neutralization. The pH of a 0.215 g sample of maleic acid dissolved in 50.00 mL of aqueous solution is found to be 1.80.

(a) Determine the empirical and molecular formulas of maleic acid.

(b) Use the results of part (a) and the titration data to rewrite the molecular formula to reflect the number of ionizable H atoms in the molecule.

(c) Given that the ionizable H atom(s) is(are) associated with the carboxyl group(s), write the plausible condensed structural formula of maleic acid.

(d) Determine the ionization constant(s) of maleic acid. If the data supplied are insufficient, indicate what additional data would be needed.

(e) Calculate the expected pH of a 0.0500 M aqueous solution of maleic acid. Indicate any assumptions required in this calculation.