The hydrogen iodide is colorless gas but hydroiodic acid is a colorless aqueous solution at standard room temperature and atmospheric pressure. We can convert hydrogen halide to hydroiodic acid and vice versa and hence, they are interconvertible.
So, Is HI a strong acid? Yes, Hydrogen iodide or hydroiodic acid is a strong acid because it can easily lose its proton. The removal of a proton from hydroiodic acid mainly depends on the bond strength of the H-I bond. The larger size of the iodine atom makes the H-I bond weaker and hence, hydrogen can be removed. The other factors such as electronegativity of the iodine atom and polarity of hydrogen iodide also contribute towards the strong acidity of hydrogen iodide. The hydrogen iodide is a very useful reagent and hence, produce useful products by the following reactions:.
Let us elaborate on this explanation for the strong acidity of hydroiodic acid or hydrogen iodide. Various scientists put different theories for defining acids and bases. Out of them, three theories have been accepted widely, namely, Arrhenius Theory, Bronsted-Lowry theory, and Lewis Theory of Acids and bases.
Let us start our discussion with the definition of acid and base via different perspectives of different scientists. However, bases are substances, which donate hydroxide ions OH- in water. This theory is based on the ionization of substances in water and hence, it is valid only for substances, which are soluble in water only.
Hence, it does not cover all substances present in nature. For example, ammonia is a base but it cannot donate hydroxide ions in water. Afterward, two theories i. It is also known proton theory of acids and bases as it explains acidity and basicity depending on their capability to lose protons or accept protons, respectively.
Hence, we can observe that the definition of acid from this theory matches with the Arrhenius Theory. Therefore, HOCl is the strongest acid and HOI is weakest, and acid strength decreases as the central halogen descends on the periodic table. Because Cl is the most electronegative, it draws the bulk of the electrons in the HOCl molecule toward itself; because H and Cl are on opposite ends of the molecule, Cl pulls at the electrons in the H-O bond, thereby weakening it.
Consider the family of chlorooxoacids, which are arranged below in order of pK a values:. The strongest acid is perchloric acid on the left, and the weakest is hypochlorous acid on the far right. Notice that the only difference between these acids is the number of oxygens bonded to chlorine.
As the number of oxygens increases, so does the acid strength; again, this has to do with electronegativity. Carboxylic acids are an important subclass of organic oxoacids, characterized by the presence of at least one carboxyl group.
Carboxylic acids are the most common type of organic acid. Acids with two or more carboxyl groups are called dicarboxylic, tricarboxylic, etc. The simplest dicarboxylic example is oxalic acid COOH 2 , which is just two connected carboxyls.
Mellitic acid is an example of a hexacarboxylic acid. Other important natural examples include citric acid in lemons and tartaric acid in tamarinds. Doubtnut is not responsible for any discrepancies concerning the duplicity of content over those questions. Study Materials. Why use Doubtnut? Instant Video Solutions. Request OTP. We seek only the relative acidity of the hydrohalides, not the absolute value.
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