Question

Which acid is the strongest: HF, HCl, HBr, HI?

• A. HF
• B. HCl
• C. HBr
• D. HI

Hint:

In binary acids of the form HX, acid strength increases as the halogen size increases, with HF being the weakest and HI the strongest.

Answer 1

The Correct Option is D

Step 1: Understanding acid strength.
The strength of an acid is determined by its ability to donate a proton. In binary acids of the form HX, where X is a halogen, acid strength increases as the size of X increases, because the bond between hydrogen and the halogen becomes weaker, making it easier to release the proton.
Step 2: Explanation.
- HF (hydrofluoric acid) is the weakest acid because the bond between H and F is very strong, making it difficult to dissociate. - HI (hydroiodic acid) is the strongest acid because iodine is the largest halogen, and the bond between H and I is the weakest, making it easier to lose the proton.
Step 3: Conclusion.
Therefore, the strongest acid among the given options is HI, corresponding to option (D).