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Potassium Iodide

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Identification
Molecular formula
KI
CAS number
7681-11-0
IUPAC name
potassium;iodide
State
State

At room temperature, potassium iodide exists as a solid, typically in granules or powder form.

Melting point (Celsius)
681.00
Melting point (Kelvin)
954.15
Boiling point (Celsius)
732.00
Boiling point (Kelvin)
1 005.15
General information
Molecular weight
166.00g/mol
Molar mass
166.0020g/mol
Density
3.1200g/cm3
Appearence

Potassium iodide is typically a white, crystalline salt that is highly soluble in water, producing a clear solution. It can sometimes appear slightly off-white or colorless depending on its purity.

Comment on solubility

Solubility of Potassium Iodide (KI)

Potassium iodide (KI) is known for its high solubility in water, making it a valuable compound in various applications. Some key points about its solubility include:

  • Highly soluble: KI can readily dissolve in water at room temperature, with solubility reaching approximately 140 g per 100 mL of water.
  • Temperature dependence: The solubility of potassium iodide increases with temperature, allowing for more significant concentrations in warmer solutions.
  • Effect of ionic strength: KI is more soluble in solutions with higher ionic strength, as the presence of other ions can interfere with the interactions between KI and water molecules.

As a result of these properties, KI solution is often used in medical and chemical applications, such as:

  • Thyroid health: It is frequently administered in medical settings to prevent iodine deficiency.
  • Chemical synthesis: KI serves as a reagent in various organic reactions due to its solubility.

In summary, potassium iodide's excellent solubility in water, along with its temperature-dependent properties, makes it a compound of interest in both scientific and medical fields.

Interesting facts

Interesting Facts About Potassium Iodide

Potassium iodide is a fascinating compound with a rich history and multiple applications in various fields. Let's explore some intriguing facts about this ionic compound:

  • Essential Nutrient: Potassium iodide plays a vital role in human health as an iodine supplement. Iodine is crucial for the production of thyroid hormones, which regulate metabolism, growth, and development.
  • Medical Uses: One of the most critical applications of potassium iodide is its use in nuclear medicine. In the event of a nuclear accident, it can help block the uptake of radioactive iodine by the thyroid gland, significantly reducing the risk of radiation-induced thyroid cancer.
  • Widespread Use in Photography: Historically, potassium iodide has also been used in photography, particularly in the preparation of photographic emulsions. It helps in enhancing the sensitivity of the film.
  • Laboratory Applications: In laboratories, potassium iodide acts as a reagent. It can be used in various chemical reactions, such as the detection of starch, where it produces a characteristic blue-black color when combined.
  • Historical Context: The discovery of iodine and its compounds, including potassium iodide, in the early 19th century led to significant advancements in both chemistry and medicine. It was during this time that scientific understanding of trace elements began to expand.

Overall, potassium iodide is more than just a simple ionic compound; its versatility and importance in health, safety, and industry make it a compound worth studying. As we continue to explore the multifaceted roles of various compounds in our lives, potassium iodide stands out due to its unique properties and critical applications.