Colour of Potassium Iodide

Potassium iodide is an inorganic compound with the chemical formula KI. It is a white crystalline solid that is soluble in water. The colour of potassium iodide depends on its state of matter and concentration.

Colour of Solid Potassium Iodide

Solid potassium iodide appears as a white crystalline powder or in the form of transparent crystals. It has no colour and is commonly used as a nutritional supplement and in medicine.

Colour of Aqueous Potassium Iodide

When potassium iodide is dissolved in water, it forms an aqueous solution. The colour of the solution depends on the concentration of potassium iodide.

- At low concentrations, the solution is colourless.
- As the concentration increases, the solution turns pale yellow.
- At higher concentrations, the solution turns dark yellow or brown.

This colour change occurs due to the formation of iodine molecules in the solution. When potassium iodide is dissolved in water, it dissociates into potassium ions (K+) and iodide ions (I-). Under certain conditions, iodide ions can react with each other to form iodine molecules (I2). The presence of iodine molecules in the solution is responsible for the yellow or brown colour.

Colour of Gaseous Potassium Iodide

Potassium iodide can also exist in the form of a gas. At room temperature and pressure, it sublimes to form a purple gas. However, this is not a common form of potassium iodide and is not relevant to its colour in most applications.

In conclusion, the colour of potassium iodide depends on its state of matter and concentration. Solid potassium iodide is white, while aqueous potassium iodide can be colourless, pale yellow, or brown depending on the concentration. Potassium iodide gas is purple, but this is not a common form.

Light orange brown...