What is the reaction & calculation when KIO3 mixed with KI, HCl by titration with Na2S2O3?
The reaction that occurs when KIO3 is mixed with KI and HCl during titration with Na2S2O3 is as follows:
2 KIO3 + 10 KI + 12 HCl → 6 KCl + 6 I2 + 6 H2O
Here's a step-by-step calculation of the titration process:
Step 1: Convert the given volume of Na2S2O3 solution used in the titration to moles.
- Let's say the volume of Na2S2O3 solution used is V1 mL, and its concentration is C1 M.
- Using the formula moles = volume (L) × concentration (M), convert V1 mL to liters by dividing by 1000: V1 L = V1 mL / 1000.
- Calculate the number of moles of Na2S2O3 used: Moles of Na2S2O3 = V1 L × C1 M.
Step 2: Determine the stoichiometry between Na2S2O3 and I2.
- From the balanced reaction, we can see that 1 mole of Na2S2O3 reacts with 1 mole of I2.
- Therefore, the moles of I2 produced in the reaction are also equal to Moles of Na2S2O3.
Step 3: Calculate the moles of KIO3 in the titration.
- From the balanced equation, we know that 2 moles of KIO3 react with 6 moles of I2.
- So, the moles of KIO3 in the reaction are given by: Moles of KIO3 = (Moles of I2 / 6) × 2.
Step 4: Determine the concentration of KIO3.
- If the initial volume of KIO3 solution used in the titration is V2 mL, and its concentration is C2 M, then the number of moles of KIO3 used can be calculated using: Moles of KIO3 = V2 L × C2 M.
Step 5: Calculate the concentration of KIO3.
- Concentration of KIO3 = Moles of KIO3 / Volume of KIO3 solution used (in liters).
By following these steps, you will be able to calculate the concentration of KIO3 in the mixture by titration with Na2S2O3.
The reaction you are referring to is the titration of KIO3 (potassium iodate) with KI (potassium iodide) and HCl (hydrochloric acid) using Na2S2O3 (sodium thiosulfate) as the titrant. In this titration, the sodium thiosulfate reacts with excess iodine generated by the reaction between KIO3 and KI. The reaction and calculation involve several steps. Here's a step-by-step explanation:
1. Balanced equation for the reaction:
2S2O3^2- + I2 → S4O6^2- + 2I^-
2. The KIO3 (potassium iodate) reacts with KI (potassium iodide) and HCl (hydrochloric acid) to produce I2 (iodine), which is the species being titrated.
KIO3 + 5KI + 3HCl → 3I2 + 3KCl + 3H2O
3. The generated iodine (I2) is then titrated with Na2S2O3 (sodium thiosulfate), which acts as a reducing agent and converts the iodine into iodide ions.
I2 + 2S2O3^2- → S4O6^2- + 2I^-
4. The titration reaction proceeds until all the iodine is converted to iodide, resulting in the appearance of a color change (from yellowish-brown to colorless) due to the formation of the colorless S4O6^2- ions.
To calculate the concentration of the KIO3, you will need to perform the titration experiment and measure the volume of Na2S2O3 solution required to reach the endpoint (color change). By knowing the concentration (in mol/L) and volume (in L) of Na2S2O3 used and using the stoichiometry of the balanced equations, you can determine the moles of iodine produced.
Here's an example calculation assuming you know the concentration and volume of Na2S2O3 used:
1. Determine the balanced equation: 2S2O3^2- + I2 → S4O6^2- + 2I^-
2. Convert the volume of Na2S2O3 used to moles using its concentration (C).
Moles of Na2S2O3 = Volume (L) x Concentration (mol/L).
3. Use stoichiometry to determine the moles of I2.
From the balanced equation, it is 1 mole of I2 for every 2 moles of Na2S2O3.
Moles of I2 = Moles of Na2S2O3 / 2.
4. Calculate the concentration of KIO3 (potassium iodate) using the reaction stoichiometry.
From the balanced equation: 1 mole of KIO3 reacts with 3 moles of I2.
Concentration of KIO3 = Moles of I2 / Volume of KIO3 solution (L).
By following these steps and performing the necessary calculations, you can determine the concentration of KIO3 in the solution.
5KI + 6HCl + KIO3 ==> 3I2 + 3H2O + 6KCl
I2 + 2Na2S2O3 ==> 2NaI + Na2S4O6
Here are the equations for the liberation of I2 and titration of same with thiosulfate. If you can't work the problem(s) from here, post with the numbers and a clear explanation of what you don't understand.