What is the formula for hydriodic acid

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The Hydroiodic Acid formula, also referred to as the Hydrogen iodide formula is discussed in this article. It is the aqueous solution of hydrogen iodide. When hydrogen iodide gas gets dissolved in water Hydroiodic Acid is obtained. In its anhydrous form is a molecule made up of a hydrogen atom and an iodine atom. The chemical formula of Hydroiodic Acid is HI.

It is a colorless liquid, with an acrid odor. which is odorless and has a cooling, saline pungent taste. Commercially it will be prepared by reacting iodine with hydrazine which provides hydrogen iodide and nitrogen gas.

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Hydroiodic Acid is an aqueous hydrogen iodide solution. It is formed when hydrogen iodide gas is dissolved in water. A molecule is composed of a hydrogen atom and an iodine atom in its anhydrous state. It is a colourless liquid with an unpleasant odour. It has a cooling, saline-strong flavour and is odourless. It is commercially prepared by reacting iodine with hydrazine, which produces hydrogen iodide and nitrogen gas. Because of the remarkable stability of its corresponding conjugate base, it is one of the strongest of the common halide acids. The chemical formula of Hydroiodic acid is HI.

Structure of Hydroiodic Acid

Hydroiodic Acid structure

Physical Properties of Hydroiodic Acid

Chemical Properties of Hydroiodic Acid

• When hydroiodic acid reacts with fuming nitric acid, it produces iodine, nitrogen oxide, and water. 

2HNO3 + 6HI → 2NO + 3I2 + 4H2O

• When hydroiodic acid reacts with a base, such as sodium hydroxide, it produces sodium iodide and water. 

HI + NaOH → NaI + H2O

Uses of Hydroiodic Acid

• It is used in the production of iodides, as a reducing agent, disinfectants, and medicines.
• One of the primary iodine sources in organic and inorganic synthesis.
• In addition to potassium iodide, hydroiodic acid is a logical choice as a source of a nucleophile in ketal deprotection.

FAQs on Hydroiodic Acid Formula 

Question 1: What happens when you consume hydroiodic acid?

Answer:

Symptoms of hydrochloric acid consumption include intense pain in the mouth and throat, drooling and breathing difficulties due to throat swelling.

Question 2: How should hydroiodic acid be stored?

Answer:

Hydroiodic acid must be stored in a dark area, in dark glass bottles that are protected from atmospheric oxygen.

Question 3: Why is hydroiodic acid such a strong acid?

Answer:

It does not entirely dissociate in water and has a reversible reaction with it. Hydrogen iodide completely dissociates in solution, making it a strong acid.

Question 4: Is HI water soluble?

Answer:

HI is a colourless gas that, when combined with oxygen, produces water and iodine. HI emits a mist (or vapours) of hydroiodic acid when exposed to moist air. It is very soluble in water and  producing hydroiodic acid.

Question 5: Is HI polar or nonpolar?

Answer:

Hydrogen iodide (HI) Note the symmetry of the molecule: When divided, the top and bottom, as well as the left and right, are not mirror reflections of one another. The molecule is also known to be polar since the bond is polar.

The aqueous solution of hydrogen iodide is called hydroiodic acid, and it is the most acidic among the hydrohalides.

Formula and structure: The chemical formula of hydroiodic acid (aq. hydrogen iodide) is HI. Its molar mass is 127.91 g/mol. Hydrogen iodide is the gaseous form, while hydroiodic acid is the aqueous solution of HI. They are both interchangeable. HI is a simple diatomic molecule with the below structure:

Hydrogen iodide is polarized because of the electronegativity of the iodide. Due to the large size of the iodide ion, the negative charge is dispersed resulting in a weaker H-I bond. This allows the H+ to be easily dissociated and hence, HI is a stronger acid than HCl, HBr and HF.

Preparation: Hydroiodic acid is prepared commercially by the reaction of iodine (I2) with hydrazine, giving hydrogen iodide and nitrogen gas.

Hydroiodic acid is also prepared by bubbling hydrogen sulfide gas through an aqueous solution of iodine.

At the end of the reaction, HI is distilled to give hydroiodic acid in the desired concentrations.

Physical properties: Hydrogen iodide is a colorless gas with an acrid odor that is readily soluble in water to give hydroiodic acid. "Concentrated" hydroiodic acid is usually 48-57% HI in water. Its exact physical properties (boiling point, melting point and density) depend on the concentration of HI in the aqueous solution.

Chemical properties: Hydroiodic acid is a strong and reactive acid. It should be used carefully due to its powerful reactivity. It can react violently with metal powders, ammonia, etc., to generate fire and explosions. It is highly corrosive, and reacts strongly with bases. HI also decomposes on heating to generate toxic fumes, and gets oxidized rapidly in air.

Uses: One of the most common uses of HI is to form alkyl iodides, an important class of organic compounds, by reacting HI with alkenes or primary alcohols. Hydroiodic acid is also a common reducing agent for various industrial purposes.

Health hazards/ health effects: The HI gas is toxic by inhalation and highly irritating to skin, eyes and mucous membranes. Hydroiodic acid can cause severe skin burns and eye damage, and is highly toxic if inhaled, ingested or absorbed through skin. Long-term exposure in low concentrations can also cause adverse health effects.

Solution of hydrogen iodide (HI) in water

Iodane[1]

Hydronium iodide

CAS Number

• 10034-85-2 
  
  Y

3D model (JSmol)

• Interactive image

• CHEBI:43451 
  
  Y

• 23224 
  
  Y

• 233-109-9

PubChem CID

• 24841

• MW3760000

• 694C0EFT9Q 
  
  N

InChI

• InChI=1S/BrH/h1H 

  
  Y

  Key: CPELXLSAUQHCOX-UHFFFAOYSA-N 

  
  Y

• InChI=1/BrH/h1H

  Key: CPELXLSAUQHCOX-UHFFFAOYAZ

SMILES

• I

Chemical formula

Solubility in water

Pictograms

Signal word

Hazard statements

Precautionary statements

3

0

0

ACID

Other anions

Related compounds

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Infobox references

Chemical compound

Hydroiodic acid (or hydriodic acid) is an aqueous solution of hydrogen iodide (HI). It is a strong acid, one that is ionized completely in an aqueous solution. It is colorless. Concentrated solutions are usually 48% to 57% HI.[2]

Reactions

Hydroiodic acid reacts with oxygen in air to give iodine:

Like other hydrogen halides, hydroiodic acid adds to alkenes to give alkyl iodides. It can also be used as a reducing agent, for example in the reduction of aromatic nitro compounds to anilines.[3]

Cativa process

The Cativa process is a major end use of hydroiodic acid, which serves as a co-catalyst for the production of acetic acid by the carbonylation of methanol.[4][5]

Illicit uses

Hydroiodic acid is listed as a U.S. Federal DEA List I Chemical, owing to its use as a reducing agent related to the production of methamphetamine from ephedrine or pseudoephedrine (recovered from nasal decongestant pills).[6]

See also

• Hydrogen iodide

References

1. ^ Henri A. Favre; Warren H. Powell, eds. (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. Cambridge: The Royal Society of Chemistry. p. 131.
2. ^ Lyday, Phyllis A. (2005). "Iodine and Iodine Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. pp. 382–390. doi:10.1002/14356007.a14_381.
3. ^ Kumar, J. S. Dileep; Ho, ManKit M.; Toyokuni, Tatsushi (2001). "Simple and chemoselective reduction of aromatic nitro compounds to aromatic amines: reduction with hydriodic acid revisited". Tetrahedron Letters. 42 (33): 5601–5603. doi:10.1016/s0040-4039(01)01083-8.
4. ^ Jones, J. H. (2000). "The Cativa Process for the Manufacture of Acetic Acid" (PDF). Platinum Metals Rev. 44 (3): 94–105.
5. ^ Sunley, G. J.; Watson, D. J. (2000). "High productivity methanol carbonylation catalysis using iridium - The Cativa process for the manufacture of acetic acid". Catalysis Today. 58 (4): 293–307. doi:10.1016/S0920-5861(00)00263-7.
6. ^ Skinner, Harry F. (1990). "Methamphetamine synthesis via hydriodic acid/Red phosphorus reduction of ephedrine". Forensic Science International. 48 (2): 123–134. doi:10.1016/0379-0738(90)90104-7.

External links

• International Chemical Safety Card 1326
• European Chemicals Bureau

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