Hydroiodic Acid Formula

The Hydroiodic Acid Formula that we also recognize as the Hydrogen iodide formula is the aqueous solution of the hydrogen iodide. When we dissolve the hydrogen iodide gas is inside the water, the Hydroiodic Acid is the thing that we get as a result. Moreover, in its anhydrous form is a molecule that is made of a single hydrogen atom and an iodine atom. However, the chemical or the molecular formula for the Hydroiodic Acid is (HI). It is a liquid that has no colour, with an acrid odour in it that is odourless and has a cooling, saline pungent taste as well. Commercially we can prepare it by the reacting iodine with the hydrazine that gives the hydrogen iodide and nitrogen gas as a result.

Hydroiodic Acid Formula and Structure

Hydrogen iodide is polarized due to the electronegative nature of the iodide. Moreover, due to the huge size of the iodide ion, the negative charge scatters and this results in a weaker H-I bond. This permits the H⁺ to be easily dissociated and hence, HI is a stronger acid if we compare it with the HCl, HBr and the HF.

The chemical formula for the hydroiodic acid is HI. Moreover, it has a molar mass of 127.91 g/mol. The hydrogen iodide is in the gaseous state, while hydroiodic acid is in the form of an aqueous solution of the HI. These both are interchangeable. Furthermore, an image showing its chemical structure is present below in the common representations that we generally use for the organic molecules:

Preparation

We can prepare the hydroiodic acid commercially by conducting the reaction of the iodine (I2) with the hydrazine, giving the hydrogen iodide and nitrogen gas as a result.

2I₂ + NH₂NH₂ → 4HI + N₂

We can also prepare the hydroiodic acid by the process of bubbling the hydrogen sulfide gas through an aqueous solution of the iodine.

H₂S + I₂ → 2HI + S

At the end of this reaction, the HI is distilled to provide the hydroiodic acid in the concentrations that we desire.

Physical Properties

The hydrogen iodide is a gas with an acrid odour that has no colour and is easily soluble when we put it inside the water to provide the hydroiodic acid. Moreover, the “Concentrated” hydroiodic acid is basically 48% to 57% (HI) inside the water. However, it’s exact and points to point physical properties such as the boiling point, melting point, and density depends upon the concentration of the HI in the aqueous solution.

Uses

One of the most common uses of the element HI is to make alkyl iodides. That is an important class of the organic compounds, by the process of reacting to the HI with the alkenes or the primary alcohols. Hydroiodic acid is a common reducing agent for various industrial purposes as well.

Health Hazards and Health Effects

The HI gas is toxic in nature, by inhalation and it can be highly irritating to the skin, to the eyes and the mucous membranes in a human being. Moreover, hydroiodic acid can result in severe skin burns and eye damages as well. Further, it is also highly toxic if we inhale it or ingest it or absorb it through our skin.

Solved Example for You:

Question: The propionic acid is subjected to reduction with hydroiodic acid in the presence of a little P. The product that we will be getting as a result is:

(A). Ethane.

(B). Propane.

(C). Butane.

(D). None of These.

Answer: (B). Propane.

Solution:

[H+] = 10-2.08 = 0.00832 mole/L

0.00832 mole/L X 0.775 L = 0.00645 mole HI

0.00645 mole HI X 127.9 g/mole = 0.824 g.