Question

What is tincture of iodine?
(A)- 2-3% solution of iodine in alcohol-water mixture.
(B)- A mixture of iodine in chloroxylenol.
(C)- A mixture of 0.2% and 2-3% iodine in water.
(D)- 2-3% solution of iodine in potassium iodide.

Answer 1

Iodine has topical antimicrobial properties and people have been using it to treat wounds for many years. Elemental iodine is proved to be toxic if ingested in amounts larger than required to disinfect.

Complete answer:
Tincture of iodine is a weak or dilute solution of elemental iodine with sodium iodide (NaI) or potassium iodide (KI) in water and alcohol. Ethanol is mostly used in forming the solution. Tincture of iodine is also known as ‘Iodine tincture’. Iodine tincture contains 2-7% of elemental iodine and the rest of the solution is constituted by either NaI or KI.
The correct option is (A)

Additional Information:
It acts primarily as an antiseptic and can be applied on cuts, scrapes and acute wounds.
It is often added in water as disinfectant against microbes like bacteria and viruses but is not effective against protozoan parasites. However, it is known to supply nutritional iodine 30 times more than the recommended allowance per day per litre.
It can also be used to sanitize the outer surfaces of fruits, vegetables and other edible products. It is found in first aid kit and emergency survival kit to disinfect wounds.
It is made available in the survival kits because it can disinfect surface water and make it fit for drinking.

Note: It is to be noted that though potassium iodide is used in making tincture of iodine but both iodine and KI are dissolved in the alcohol-water medium. We may mistake option (D) as the answer but it is not the case since tincture of iodine is not the solution of iodine in KI medium.