Iodine is a chemical non-metallic element with the symbol ‘I’ and atomic number 53 in the periodic table. It is a member of the halogen family which is less reactive and mainly found on earth as water-soluble form.
Physical and Chemical Properties
- Iodine is a black shiny crystalline and lustrous solid element
- It is least reactive and most electropositive halogen
- It sublimes easily on heating to give the purple vapour
- It is soluble in solvents like carbon tetrachloride and slightly in water.
- It has a melting point of 114℃ and boiling point of 184℃
- It has a density of 4.93gm-3 at 20℃
- It is used for medical treatment as a tincture and iodoform
- It is used in the manufacture of some printing inks and dyes.
- Silver iodide is used in photography
- It is used as a supplement to animal feed
- It is the main ingredient for water purification for drinking water
- It is added in a small amount to table salt to avoid iodine deficiency affecting the thyroid gland
Iodine in the Environment
Iodine is found as iodide in seawater and is assimilated by seaweeds. It is an ingredient of bread and ocean plants. Some aquatic plants and organisms will store in their tissues.
The important sources of natural iodine are in oceans and it escapes from the ocean as iodide about million tones in a year. It can combine with water and precipitate into water or oil that further combines with organic matter in the soil. Plants will absorb for their growth as well as cattle will consume when they eat plants.
It can be seriously harmful to the environment as it can form radioactive species which has a half-life of million. So it can act as both environments friendly as well as an enemy.
Sucrose is a disaccharide composed of two monosaccharides namely glucose and fructose having a formula of C12H22O11. It is a colourless sweet-tasting crystal. It naturally occurs in sugar cane, sugar maple sap, dates, and honey. It is prepared commercially in large amounts by different methods.
Physical and Chemical properties
- It is hard and solid at room temperature
- It is a white-coloured monocrystal having a melting point -186℃.
- It has the ability to convert dry solid to a liquid when heated properly.
- When heated at 338 degrees Fahrenheit, sucrose begins to caramelize.
- It has the ability to dissolve in water
- It is a flammable substance and can ignite in a gentle flame
- Sucrose is the main ingredient in honey and dates.
- It is used in many pharmaceutical products
- It is an important component of soft drinks and beverages.
- It acts as a food stabilizer
- It also uses as an antioxidant and food preservatives
The iodine test is used to test for the presence of starch. If we add an aqueous solution of triiodide anion, the solution will turn into a blue-black colour. In the absence of starch, it remains as such. The intensity of colour decreases with increase in temperature. When we add an iodine solution to sucrose, there will be no colour change, the solution remains dark brown in colour.
- Iodine is a non-metallic black and glittering element having a symbol “I” in the periodic table.
- It is a least reactive and most electropositive halogen that helps for medical treatments.
- Silver iodide is used in photographies.
- It occurs in oceans and consumed by aquatic plants and animals
- Sucrose is a disaccharide composed of two monosaccharides namely glucose and fructose and has a white crystalline appearance.
- It is the main ingredient for the dates and sugar maples.
- Iodine test will be negative for sucrose whereas positive for starch.