Option 4: Potassium chloride is used in the preparation of antiseptic solutions. Antiseptics are substances that kill or inhibit the growth of microorganisms, preventing infection in wounds or on the skin. Potassium chloride is commonly used as a component in antiseptic solutions due to its antimicrobial properties.

Potassium chloride is a salt that contains potassium and chlorine ions. It has a bactericidal effect, meaning it can kill bacteria. When used in antiseptic solutions, it disrupts the cell membrane of bacteria, leading to their death. Additionally, potassium chloride can also help in reducing inflammation and promoting wound healing.

Options 1, 2, and 3 are not commonly used in the preparation of antiseptic solutions.

Option 1: Potassium nitrate is a compound used in fertilizers, toothpaste, and pyrotechnics. It does not have specific antimicrobial properties.

Option 2: Iodine is commonly used as an antiseptic itself in the form of iodine solution or iodine tincture. However, it is not used in the preparation of antiseptic solutions that contain potassium chloride.

Option 3: Iodine chloride, also known as iodine(I) chloride, is primarily used