A 5.00 mL sample of filtered orange juice was treated with 50.00 mL of 0.01023 M I3 – to oxidize ascorbic acid to dehydroascorbic acid. After the oxidation was complete, excess I3 – was back-titrated with 13.82 mL of 0.07203 M Na2 S2O3 to starch indicator end point. What is the concentration of ascorbic acid in the orange juice? Report the concentration ascorbic acid in mg/100 mL.  C6H8O6 + I3 – → C6H6O6 + 3I - + 2H+  I3 – + 2S2O3 2- → S4O6 2- + 3I2  Answer: 48.5  mg/100 mL

In Aspirin lab preparation a student used 69.0 g of salicylic acid and 30.0 g of acetic anhydride. Write the general balanced equation and calculate the reaction efficiency, if the pure aspirin was 0.25 mole. Why did you use phosphoric acid in the reaction?

After a student determined the pK values of a H3PO4 by titration, she realized that she had recorded on her data sheet that the concentration of NaOH used in the titration was 0.25 M, but her partner had filled the buret with 0.20 M NaOH.  Would you expect the calculated pK values to be correct or incorrect?  Explain your reasoning.

Under the conditions of this extractive procedure, how does aspirin become partitioned into the aqueous layer? How do we then recover this substance in a pure form from the aqueous layer? O 1) The acidic hydrogen in the carboxyl group (-COOH) of aspirin undergoes an acid-base reaction with NaOH to form the conjugate base, sodium 2-acetoxybenzoate. U 2) This ionic species then readily dissolves in water. 3) Conversely, the organic unknown does not possess an acidic residue, so no acid/base reaction can occur. 4) It therefore does dissolve in water.

To synthesize methyl 3-nitrobenzoate, 20 ml of H2SO4 and 10 g of methyl benzoate were used. The nitrating mixture was prepared using 6 ml of H2SO4 and 6 ml of HNO3. Calculate the molar ratio of sulfuric acid to nitric acid

3. What were the structural features of the molecules that were soluble in aqueous bases (5% NaOH and 5% NaHCO3) and why do these features allow these molecules to dissolve in that solvent? 4. What were the structural features of the molecules that were soluble in aqueous acid (5% HCl) and why do these features allow these molecules to dissolve in that solvent? Solubility of Known Compounds Lab Known compounds: Glycerol, Sec-butanol, Naphthalene, Triphenyl methanol, Aniline, Benzoic Acid, Dioctyl Sebacate..

what of reactants are being used in CaI2+Na2C2O4=CaC2O4+2NaI