As a specialist in the field of chemistry, I can provide you with an in-depth analysis of the strength of acids. When we discuss the strength of an acid, we are generally referring to its ability to donate a proton (H+) in a solution. The strength of an acid is often quantified by its dissociation constant, denoted as Ka, and its corresponding pKa value, which is the negative logarithm of Ka.

Hydrochloric acid (HCl), hydrobromic acid (HBr), and hydroiodic acid (HI) are all examples of hydrohalic acids, which are the hydrogen halides of the halogens. These acids are known for their ability to completely dissociate in water, making them strong acids.

The strength of an acid is not solely determined by its ability to dissociate but also by the stability of the conjugate base that is formed after the acid has donated its proton. The pKa value is a measure of this stability. A lower pKa value indicates a stronger acid because it means that the acid has a greater tendency to donate its proton and form the conjugate base.

In the case of HCl, HBr, and HI, the pKa values are as follows:
- HI has a pKa of approximately -9.3.
- HBr has a pKa of approximately -8.7.
- HCl has a pKa of approximately -6.3.

From these values, we can see that HI is the strongest acid among the three, followed by HBr, and then HCl. This is because the ability to donate a proton increases down the halogen group due to the increasing size and decreasing electronegativity of the halogens. As the size of the halogen increases, the bond strength between the hydrogen and the halogen decreases, making it easier for the hydrogen to be donated as a proton.

However, it is important to note that in the context of aqueous solutions, all three acids are considered strong acids and will dissociate completely to form hydronium ions (H3O+) and the respective halide ions (Cl-, Br-, I-). The difference in their pKa values becomes less significant in this context because the primary factor determining the strength of an acid in water is its ability to donate a proton, which all three do effectively.

In summary, while HI is the strongest acid of the three in terms of pKa, in an aqueous solution, HCl, HBr, and HI are all strong acids and will behave similarly with respect to their dissociation and protonation of water.

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It isn't. In terms of dissociation, HI has a pKa of -9.3 and HBr has a pKa of -8.7 compared to the pKa of HCl at -6.3. ... In water, however, functionally they are basically of equal strength because they are all stronger acids than the hydronium ion, which means that they will dissociate and protonate water to completion.read more >>