Question

The vinegar in this titration was distilled vinegar which is colorless. what modifications would we need to do in this procedure so that we could test OTHER solutions such as cider vinegar or pickling liquor which both have a SIGNIFICANT COLOR

it requiretion? (All of the hydrofion of this reacti la S- g the Solution. The water does not Cause any any no matter che change how in the # of er moles of CH₃COOH how much water is thing added. happening The only se is a dilution of the sample but 2. A 25.00 mL sample of a sulfuric acid solution (H.SO) is titrated with sodium hydroxide (NaOH). If it requires 35.88 mL of 0.1127 M NaOH to reach the endpoint what is the molarity of the sulfunc che sulfurics acid solution? (All of the hydrogens of the sulfuric acid react with the sodium hydroxide.) Hints Write a balanced chemical equation of this reaction first. HSO4 +2NaOH - Na, Soy +ZH2O H-34 H-X4 36 Na x2 na x2 Vol H2SO4 = 2 s.comL *.00) = .0251 vo | Ma OH = 35.88 PC * ,0O1 = 035%8C hoovaot = 1127 ASIL erity of NaOH = -1127 mol 1x x.03 5888 = 14.0436 76 xious mol 1 2 = 2.02 x10 moles Molarity of Hasou = 2.02 x 10-3 moles -1.08M ozsL - 3. The vinegar in this titration was distilled vinegar and is clear and colorless. What modifications Would you need to do to this procedure in order to test solutions such as cider vinegar or pickling liquor, both of which have significant color? Page 9 of 10

Answer 1

For cider vinegar or pickling liquor having a yellowish colour, phenolphthalein as the acid-base pH indicator can not be used as the colour of the solution will mask the end point of the titration i.e appearence of pale pink color. Thus, some other indicator that changes colour in the pH range 8-10 i.e the end-point of the acetic acid and sodium hydroxide titration, should be used, For example thymol blue (second range: 8.0-9.6) that changes color from yellow to blue or thymolthalein (9.3-10.5) that changes from colorless to blue should be used instead of phenolphthalein indicator.