-What ions are present in the titrated solution after the beginning of the titra
ID: 493710 • Letter: #
Question
-What ions are present in the titrated solution after the beginning of the titration but before the equivalence point? How about after the equivalence point when the conductivity is rising? Lastly, compare your results from 2 and 4 above with the actual molarity of the Ba2+ in the solution. Which method of analysis, equivalence point or gravimetric determination, was more accurate in your experiment? Why? Trial 2 T Trial 3 Trial 1 Equivalence point (mL) Mass of filter paper Precipitate (g 32 Mass of filter paper (g Mass of precipitate (g) of H2SO4 Mola DATA ANALYSIS (Show examples of each calculation for credit) 1. Use the titration results to calculate the moles of H.soathat were used to reach the equivalence point in each trial. The equivalence point is most accurately determined from the intersection of he best fit lines of the data points on your plots before and after the equivalence MaA moles conc x vol. 2. Use your titration results to calculate the molar concentration (molarity) of Ba? ion in the ar amount of H2Sou used in each trial. 3. Convert the mass of the barium sulfate precipitate, formed in cach trai to moles. lo37 383 233.38 olarity of the Ba(OH) solution. moles of Ba (OH)2 (A) Baso 36
Explanation / Answer
BaOH is strong base it completely ionises in water giving Ba2+ and OH-
BaSO4 is only negligibly soluible in water, so after beginning of titration and before reaching equivalence point Ba2+ and OH- are present in solution
So the conductivity is due to Ba2+ and OH- as the titration proceeds BaSO4 and H2O is fomed due t this conductivity decreases,at equivalent point conductivity is low after equivalent point conductivity increases sharply due to addition of H+ ions whose mobility is very much higher
1. Volume of slfuric acid in litres = 8/1000 = 0.008 L
Moles of slfuric acid = molarity x volume in litre
= 0.1 M/L × 0.001L = 0.00001 M
2. Moles of Ba2+ = moles of H2SO4 used= 0.00001M
3. moles = mass/ molar mass of barium sulfate
= 0.1637/233.383 = 0.0007
4. moles of barium sulphate formed= moles of barium hydroxide
= 0.0007
Molarity = moles/ volume of barium hydroxide taken in litre for titration
Equivalence point method is more accurate, gravimetric method involves loss of precipitate during filtration, proper drying is required, proper temperature and experimental conditions are required, errors in these things add up, as a result the method is not accurate when compared to conductometric titration
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