Sodium thiosulfate, Na2S2O3, is an important reagent for titrations. Its solutions can be standardized
by titrating the iodine released when a weighed amount of potassium hydrogen iodate, KH(IO3)2 (389.912
g/mol), is allowed to react with excess potassium iodide in acidic solutions. The net ionic equations are:
production of iodine from KH(IO3)2: IO3
–
+ 5 I–
+ 6 H+
→ 3 I2 + 3 H2O
titration of iodine: I2 + 2 S2O3
2– → 2 I–
+ S4O6
2–
What is the molarity of a sodium thiosulfate solution if 37.76 mL are required to titrate the iodine releasedfrom 0.1650 g of KH(IO3)2? I got 0.01345. I really need to know of I am even remotely close asap
The digits are right but you are off by a factor of 10. It should be 0.1345 M.
Looks like youve got his handled drbob
To find the molarity of the sodium thiosulfate solution, we can use the stoichiometry of the titration reaction. Here are the steps to calculate it:
1. Calculate the number of moles of KH(IO3)2:
- Convert the mass of KH(IO3)2 to moles using its molar mass:
Moles of KH(IO3)2 = (0.1650 g) / (389.912 g/mol)
2. Use the stoichiometry of the iodine production reaction to find the moles of iodine produced:
- From the balanced equation, we see that 1 mole of KH(IO3)2 produces 3 moles of iodine.
Moles of iodine produced = 3 * (moles of KH(IO3)2)
3. Calculate the molarity of the sodium thiosulfate solution:
- The balanced equation shows that 1 mole of iodine reacts with 2 moles of sodium thiosulfate.
- Use the formula: Molarity = (moles of sodium thiosulfate) / (volume of sodium thiosulfate solution in liters)
- Convert the volume of the sodium thiosulfate solution from mL to L.
- Molarity = (2 * (moles of iodine)) / (volume of sodium thiosulfate solution in liters)
4. Substitute the calculated values into the formula above to find the molarity of the sodium thiosulfate solution.
Please perform the calculations using the given values and let me know if you need any further assistance.
To find the molarity of the sodium thiosulfate (Na2S2O3) solution, you need to use the information provided about the titration.
First, let's calculate the number of moles of potassium hydrogen iodate (KH(IO3)2) used. We are given the mass of KH(IO3)2, which is 0.1650 g, and its molar mass, which is 389.912 g/mol. Using the formula:
Number of moles = Mass / Molar mass
Number of moles of KH(IO3)2 = 0.1650 g / 389.912 g/mol
Next, we need to use the stoichiometric coefficients from the balanced net ionic equation to find the number of moles of iodine (I2) produced. From the equation:
1 mol of KH(IO3)2 produces 3 mol of I2
Number of moles of I2 = Number of moles of KH(IO3)2 × (3 mol I2 / 1 mol KH(IO3)2)
Now, let's use the volume of sodium thiosulfate solution used in the titration, which is 37.76 mL. The molarity (M) is defined as the number of moles of solute divided by the volume of the solution in liters.
Volume of sodium thiosulfate solution in liters = 37.76 mL × (1 L / 1000 mL)
Finally, we can calculate the molarity of the sodium thiosulfate solution using the formula:
Molarity = Number of moles / Volume in liters
Molarity = Number of moles of I2 / Volume of sodium thiosulfate solution in liters
Now, let's plug in the values:
Molarity = (Number of moles of KH(IO3)2 × (3 mol I2 / 1 mol KH(IO3)2)) / (37.76 mL × (1 L / 1000 mL))
Molarity = (0.1650 g / 389.912 g/mol) × (3 mol I2 / 1 mol KH(IO3)2) / (37.76 mL × (1 L / 1000 mL))
Calculating this expression will give you the molarity of the sodium thiosulfate solution.