Iodized salt is a mixture of potassium iodide and common salt.

Option 1: This is the correct answer. Iodized salt is made by mixing potassium iodide, which is a source of iodine, with common salt (sodium chloride). The purpose of adding potassium iodide is to ensure that the resulting salt contains a sufficient amount of iodine, which is an essential nutrient for the human body.

Option 2: This option is incorrect. Iodized salt does not typically contain molecular iodine, as it is too reactive and volatile to be used directly in salt production.

Option 3: This option is incorrect. Although both potassium iodide and common salt are involved in the production of iodized salt, they do not form a compound together. They remain as separate components within the mixture.

Option 4: This option is incorrect. Like option 2, iodized salt does not contain molecular iodine. It is usually in the form of potassium iodide.

In summary, the correct answer is option 1, as iodized salt is a mixture of potassium iodide and common salt.