How would you usually prepare starch indicator solution for iodine titrations? Can the solution be stored for a few months in the fridge?

I noticed that sometimes the starch indicator solution in the fridge has turned cloudy, in which case we should prepare a new solution?

I've never tried storing starch indicator in a refrigerator. I've ALWAYS made it fresh and use it the same day. I don't trust it more than a day although I've seen it stay ok for 2-3 days. Still, it's so easy to make I make it fresh each day.

To prepare a starch indicator solution for iodine titrations, follow these steps:

1. Start by weighing a small amount of starch (around 0.5 grams) into a beaker or flask.
2. Add a small volume of distilled water (around 10 mL) to the starch and stir to make a paste.
3. Boil water in a separate flask or beaker, and then slowly add it to the starch paste while stirring continuously.
4. Continue stirring until the starch paste is well-dissolved and forms a clear, smooth solution.
5. Allow the starch indicator solution to cool down to room temperature before using it in iodine titrations.

Regarding the storage of the starch indicator solution in the fridge, it is generally recommended to prepare a fresh solution when needed and not store it for extended periods. This is because the starch indicator solution can degrade over time. Additionally, the cloudiness you observed may be a sign of bacterial growth or degradation of the starch. In such cases, it is best to prepare a new solution to ensure accurate results in your iodine titrations.

To prepare starch indicator solution for iodine titrations, you can follow these steps:

1. Take a small amount of starch (around 1 gram) and add it to a beaker or flask.
2. Add a few milliliters of distilled water to the starch and mix it thoroughly to form a paste.
3. Heat the mixture gently while stirring until it becomes a translucent gel.
4. Gradually add more distilled water while stirring continuously until the desired volume is reached.
5. Allow the mixture to cool down to room temperature before using it as an indicator for iodine titrations.

Now, regarding storage of the starch indicator solution in the fridge, it is generally recommended to prepare fresh solution whenever needed because starch solutions are prone to microbial growth and degradation over time. However, if you need to store the solution for a short period, it can be refrigerated. But keep in mind a few points:

1. Use a clean and sterilized container that is tightly sealed to minimize contamination.
2. Label the container with the preparation date to track its age.
3. To prevent microbial growth, you can add a few drops of a preservative like chloroform or thymol solution to the starch indicator solution before storing it.

If you notice any cloudiness or change in appearance of the starch indicator solution when taken out from the fridge, it is advisable to prepare a new solution. The cloudiness may indicate microbial growth or degradation of the starch, which could affect the accuracy of your iodine titrations.