Skip to content
Related Articles
Get the best out of our app
Open App

Related Articles

Oxoacids of Halogens – Definition, Properties, Structure

Improve Article
Save Article
Like Article
Improve Article
Save Article
Like Article

The elements of Group 17 from top to bottom are fluorine, chlorine, bromine, iodine, and astatine. They are referred to as halogens because they create salt. This group’s members are very similar to one another. They have a consistent pattern of physical and chemical features. The valence shell of each of these elements contains seven electrons. Their electronic setup is ns2 np5.

If the acid contains oxygen (referred to as an oxoacid), the suffixes –ous and –ic are used again to signify the lower and larger number of oxygens in the acid formula. Oxoacids are composed of hydrogen, oxygen, and other elements. Acids that contain hydrogen, oxygen, and another element are known as oxyacids.

Group 17 Elements: The Halogen Family

Group 17 is the sixth p-block element group. The term Halogens is derived from the Greek words Halo and genes. Halogen is derived from the words halo, which means salt, and genes, which means born, so halogen implies salt producers. When interacting with alkali metals or alkali earth metals, all elements in group 17 create salts. As a result, this group is also known as the Halogen family, and the elements in this group are known as halogens.

Oxoacids of Halogens

Fluorine, chlorine, bromine, iodine, and astatine are all members of Group 17. They are collectively referred to as halogens, which means salt makers. This group’s members are strikingly similar. As we progress down the group, there is a consistent gradation in physical and chemical properties. We can’t separate them in their pure form. In an aqueous solution, they are stable. They are also extremely stable in salt form. Hypohalous acids (+1 oxidation state), halous acids (+3 oxidation state), halic acids (+5 oxidation state), and perhalic acids (+7 oxidation state) are the four types of oxoacids produced by halogens.

Astatine is the group’s lone radioactive element. Their valence shell has seven electrons (ns2 np5), one less than the next noble gas configuration. Because of their effective nuclear charge, halogens have a modest size. As a result, they are less likely to lose electrons and more likely to gain an electron to complete their octet. Several oxoacids are formed by halogens (they are acids that contain oxygen in the acidic group).

Properties of Halogen Oxoacids

  1. Fluorine is quite tiny and has a high electronegativity. As a result, it only produces one oxoacid, HOF, which is also known as fluoric(I) acid or hypofluorous acid. The other members of the halogen family combine to generate a number of oxoacids. They can’t be isolated in their pure form. They are stable in aqueous solutions or as salts.
  2. In general, halogens generate four types of oxoacids: hypohalous acids (+1 oxidation state), halous acids (+3 oxidation state), halic acids (+5 oxidation state), and perhalic acids (+7 oxidation state).
  3. Chlorine may be broken down into four types of oxoacids. That is, HOCl (hypochlorous acid), HOClO (chlorous acid), HOClO2 (chloric acid), and HOClO3 (hypo chloric acid) (perchloric acid).
  4. Bromine produces HOBr (hypobromous acid), HOBrO2 (bromic acid), and HOBrO3 (hypobromous acid) (perbromic acid). Iodine decomposes into HOI (hypoiodous acid), HOIO2 (iodic acid), and HOIO3 (hypoiodic acid) (periodic acid).

Structures of the oxoacids of halogens

The core halogen atom is sp3 hybridized in all oxoacids. Every oxoacid contains at least one X-OH bond. “X=O” linkages are present in the majority of these oxoacids. In nature, the double bond between the central halogen atom and oxygen in an oxoacid is d pi – p pi. Hypofluorous acid, hypochlorous acid, hypobromous acid, and hypoiodous acid are examples of hypohalous acids. In hypohalous acids, the halogen has an oxidation state of +1. Because of the existence of three lone pairs of electrons on the central halogen atom, the hypohalite ions have a linear form.

Hypochlorous Acid

Because hypohalous acids are less stable, they tend to create halic acids.

3HOX → HOXO2 + 3HX

Only fluorine oxoacid is hypofluorous acid. Due to the lack of d orbitals in the fluorine atom, no higher oxoacid of fluorine is known. Only chlorous acid is included in the halous acids. The oxidation state of chlorine in chlorous acid is +3. Because of the existence of two lone pairs on the core chlorine atom, the chlorite ion displays a V shape. Chloric acid, bromic acid, and iodic acid are examples of halic acids. In these oxoacids, the halogen has an oxidation state of +5. Because of the presence of a lone pair of electrons on the central halogen atom, the halite ions have a pyramidal structure.

Chlorous Acid

Perchloric acid, perbromic acid, and periodic acid are examples of perhalic acids. The halogen oxidation state of these oxoacids is +7. The perhalate ion has a tetrahedral structure. The first member of any sequence of halogen oxoacids has high acidic strength. This is because the halogens have a strong electro-negativity and are tiny in size.

Chloric Acid

Perchloric Acid

Perchloric acid, for example, has a high acidic strength among perhalic acids. Because chlorine is more electronegative than bromine or iodine, the shared electron pair in a Cl-O bond is closer to chlorine than bromine in a Br-O bond or iodine in an I-O bond. As a result, in the case of perchloric acid, the O-H bond becomes substantially weaker, allowing for the easy release of a proton. The acidic strength of an oxoacid grows as the halogen’s oxidation number increases.

Interhalogen Compounds

Interhalogen compounds are those that result from the reaction of two distinct halogens. They have general compositions of XX′, XX3′, XX5′, and XX7′, where X is a larger halogen and X′ is a smaller halogen, and X is more electropositive than X′. As the ratio of the radii of X and X′ grows, so does the number of atoms per molecule.

Sample Problems

Question 1: What are the uses of halogen?


The following are some of the most prevalent applications for halogens:

  1. Fluorine compounds are commonly found in toothpaste and drinking water supplies. Fluorine is a very important drug because it is strongly reactive with tooth enamel and delays tooth decay.
  2. Chlorine is widely utilised in the bleaching process. It is also used in the metallurgy of gold and platinum.
  3. Chlorine is a chemical that is used to purify drinking water.
  4. Iodine is an antiseptic and a good germicide.

Question 2: What are interhalogen compounds?


When halogens react with one another, interhalogen compounds are created. Their features and behaviours are midway between those of two-parent halogens. However, some features may differ. Except for IF7, all interhalogens can be created by mixing pure halogens under specific conditions.

Question 3: What are the oxidation states exhibited by halogens?


The elements of the halogen family all have a -1 oxidation state. Fluorine, the most electronegative element, has only a -1 oxidation state. Elements with +1, +3, +5, and +7 states include chlorine, bromine, and iodine.

Question 4: How do halogens react with oxygen?


When halogens react with oxygen, oxides are generated. However, it has been discovered that the oxides are unstable. In addition to oxides, halogens form a range of halogen oxoacids and oxoanions.

Question 5: Are halogens good oxidizing agents?


The halogens are all excellent oxidizers. Fluorine is the most potent oxidizer on the list. It is capable of converting all halide particles to halogen.

My Personal Notes arrow_drop_up
Last Updated : 15 Feb, 2022
Like Article
Save Article
Similar Reads
Related Tutorials