A solution of I2 was standardized with ascorbic acid. Using a 0.0500 g sample of the acid, 26.50 mL of I2 were required to reach the starch end point.
assume the question is to determine M I2.
ascorbic acid + I2 ==> 2I^= + .....
mols ascorbic acid = grams/molar mass
mols I2 = mols ascorbic acid (1:1 ratio from the equation)
M I2 = mols I2/L I2.
To determine the concentration of the I2 solution, we need to calculate the number of moles of I2 that reacted with the ascorbic acid in the given sample.
Here's how we can do it step by step:
1. First, calculate the number of moles of ascorbic acid using its molar mass (C6H8O6 = 176.12 g/mol) and the mass of the sample (0.0500 g):
Moles of ascorbic acid = mass / molar mass
= 0.0500 g / 176.12 g/mol
2. Next, we need to determine the stoichiometry of the reaction between ascorbic acid and iodine (I2). From the balanced equation, we know that one mole of ascorbic acid reacts with one mole of iodine:
C6H8O6 + I2 --> C6H6O6 + 2HI
This means that the number of moles of iodine reacted will be the same as the number of moles of ascorbic acid used.
3. Now, we can calculate the concentration of the I2 solution using the volume of I2 used (26.50 mL or 0.0265 L) and the number of moles of iodine reacted:
Concentration of I2 solution = moles of I2 / volume of I2 solution
4. Finally, convert the concentration to a more commonly used unit, such as Molarity (M), by dividing by the volume of the I2 solution used in liters:
Molarity (M) = Concentration of I2 solution / Volume of I2 solution (in liters)
By following these steps, you can determine the concentration of the I2 solution.