Hydrogen Iodide is colorless gas and also reacts with oxygen to give iodine and water. It is produce hidroiodic acid during reaction with moist. It is soluble in water and gives hidroiodic acid. 425 liters of HI gas soluble into 1 liter of water. Hydrogen iodide is a primary source of iodine.

Here we describing about how to produce hydrogen iodide in lab.

Mostly in industrial preparation Iodine reacts with hydrazine to produce HI and this reaction produce nitrogen gas as its extra components. The reaction is follows

2 I₂ + N₂H₄ → 4 HI + N₂

The hydrogen iodide must be distilled to forming this reaction. For getting distilled HI must pass this gas through the solution of sodium iodide or through any alkali iodide like phosphoric acid. Do not distill hydrogen iodide through sulfuric acid because sulfuric acid oxidize iodide and produce elemental iodine.

One another way to produce hydrogen iodide by passes the hydrogen sulfide stream through aqueous solution of iodine. This reaction produces hydroiodic acid with sulfur. Sulfur can be filtered through filtration process and we get HI. The reaction is follows

H₂S +I₂ → 2 HI + S

Another way to produce hydrogen iodide by simply react hydrogen with iodine. You can imply this method when you need high quality sample. The reaction of this method is

H₂ + I₂ → 2 HI

This reaction is considered as simple bimolecular reaction between two molecules of Iodine and Hydrogen. This reaction is happen in present of 578 nanometer radiation of light. The mechanism of this reaction is Iodine first dissociate into 2 molecules of Iodine atom and then each molecule attach hydrogen bonds by side chain and after that hydrogen is broken into H—H bond. The reaction is follows

H₂ + I₂ + 578 nm radiation → H₂ + 2 I → I - - - H - - - H - - - I → 2 HI

Another methods of to produce HI in lab is by using phosphorus. At first iodine react with phosphorus to make phosphorus triodide then this phosphorus triodide react with water to make Hydrogen Iodide and phosphorus acid. The reaction is follows

3 I₂ + 2 P + 6 H₂O → 2 PI₃ + 6 H₂O → 6 HI + 2 H₃PO₃

So here we can see too many methods to produce hydrogen Iodide in labs. Hydrogen Iodide is use to make Hydriodic acid. This acid is use to increase Iodine level in salt.

Diatomic molecular hydrogen iodide is a colorless gas. In aqueous solution it makes a strong acid that is known as hydroiodic acid or iohydroic acid. Both the solutions of hydrogen iodide that is aqueous solution and gaseous solutions are interconvertible. hydrogen iodide or HI is a reducing agent and is a rich source of iodine. The molecules are soluble in water and give strong acids in solutions. When this colorless gas reacts with oxygen, it produces water and iodine. Reaction of HI with moisture results in the formation of hydroiodic acid.

The production of HI in laboratory involves the following methods:

The industrial method involves reaction of hydrazine and iodine to form HI. Nitrogen gas is produced as additional product. The chemical reaction for this process is-

2 I2 + N2H4 → 4 HI + N2

In order to carry out the above reaction, it's a must to use distilled hydrogen iodide. For distillation, the gas should be passed through sodium iodide solution. The gas can also be passed through an alkaline iodide such as phosphoric acid. One thing to remember is that the gas should not be passed through an oxidizing agent like sulfuric acid as it produces element iodine on oxidizing the iodide.

You can also produce HI in lab by passing the stream of hydrogen sulfide through an aqueous iodine solution. As a result of the reaction, sulfur and hidroiodic acid are produced. In order to get Hi sulfur should be filtered. Filtration process can be carried out for filtering sulfur. The reaction for this process is as follows-

H2S +I2 → 2 HI + S

A simple reaction of hydrogen and iodine also gives HI. This method can be applied in order to get a sample of high quality. The reaction is as follows-

H2 + I2 → 2 HI

This is a reaction between the molecules of hydrogen and iodine and is a bimolecular reaction. In this reaction, dissociation of iodine takes place into two molecules and this is followed by the attachment of hydrogen bond. Breaking of hydrogen into H-H bond takes place after this. The reaction for this process is given below-

H2 + I2 → H2 + 2 I → I - - - H - - - H - - - I → 2 HI