Consider the titration described here:

• 0.7917 g of anhydrous sodium thiosulphate (Na ₂  S ₂  O ₃  ), previously purified and dried in an oven, is weighed into an erlenmeyer flask.
• This sample is titrated with a mixture of KIO ₃  and KI that contains approximately 0.1 M I ₃  ^-  . This titration requires 23.56 mL of titrant to reach the endpoint (found with a starch indicator).
• This same mixture of KIO ₃ and Kl is then used to titrate a solution containing an unknown amount of ascorbic acid. This titration requires 37.21 mL of titrant to reach the endpoint (found with a starch indicator).
• The ascorbic acid sample used in the titration above was prepared by using a 25 mL pipet to deliver an aliquot of the solution into an erlenmeyer flask.

Relevant reactions:

Based on this information, what is the concentration (in mol/L) of ascorbic acid in the "unknown" liquid?

Transcribed Image Text:

13 +2 S203²31 +S406² {ascorbic acid} +13 + H₂O = {dehydroascorbate} + 31¯¯¯ + 2H+ 13 +2 S203²31 +S406² {ascorbic acid} +13 + H₂O = {dehydroascorbate} + 31¯¯¯ + 2H+

Answer rating: 100% (QA)

ANSWER In this titration iodine is generated by the reaction of potassium iodate KIO3 and potassium ... View the full answer