Answer to Question #326104 in Chemistry for Kaye

Question

 A 0.8160-g sample containing dimethylphthalate, C6H4(COOCH3)2 (194.19 g/mol), and un-reactive species was refluxed with 50.00 mL of 0.1031 M NaOH to hydrolyze the ester groups (this process is called saponification).

C6H4(COOCH3)2 ⫹ 2OH⫺ : C6H4(COO)2⫺ 2 ⫹ 2CH3OH

After the reaction was complete, the excess NaOH was back-titrated with 24.27 mL of 0.1644 M HCl. Calculate the percentage of dimethylphthalate in the sample.