The strength of an I2 solution may be verified by reacting the I2 with thiosulfate.
I2 + 2(SO2O3) == 2I + S4O6
(I is for iodine)
15.0 mL of an iodine solution of unknown molarity was titrated against a 0.00100 M solution of S2O3. The blue black iodine starch complex just disappeared when 20.0 mL of thiosulfate was added. What is the exact molarity of the I2 solution?
To find the exact molarity of the I2 solution, we can use the concept of stoichiometry and the balanced chemical equation provided.
Here's how you can solve the problem step-by-step:
1. Write the balanced chemical equation:
I2 + 2S2O3 -> 2I- + S4O6^2-
2. Determine the stoichiometric ratio between I2 and S2O3:
From the balanced equation, we can find that 1 mole of I2 reacts with 2 moles of S2O3.
3. Calculate the number of moles of S2O3 used:
Moles of S2O3 = Molarity of S2O3 * Volume of S2O3
Moles of S2O3 = 0.00100 M * 20.0 mL
Note: Convert the volume from mL to liters by dividing by 1000.
4. Use the stoichiometric ratio to determine the number of moles of I2:
Moles of I2 = (Moles of S2O3) / 2
5. Calculate the molarity of the I2 solution:
Molarity of I2 = Moles of I2 / Volume of I2 (in liters)
Note: The volume of the I2 solution is given as 15.0 mL, so convert it to liters by dividing by 1000.
By following these steps, you will find the exact molarity of the I2 solution.