Based on their molecular structure, why are these acids thes stronger of the two binary acids given?

HCl stronger than HF
HF stronger than H2O
H2Se stronger than H2S
Is this because of bond strength due to placement on the table of elements? thanks

When you go DOWN the periodic table the acidity increases as the size of the atom (the non-hydrogen atom) increases. As you go ACROSS the periodic table (from left to right), it's the electronegativity of the non-hydrogen atom. Thus HF<HCl<HBr<HI and H3N<H2O<HF.

Thank you so much for ALL your help. You make it so simple and easy to understand.

Yes, the strength of acids can be explained based on their molecular structure and position on the periodic table. There are a few factors that determine the strength of an acid, including bond strength and polarity.

In the case of binary acids, the strength is often determined by the polarity of the bond between the hydrogen atom and the other atom in the acid. The more polar the bond, the stronger the acid.

Let's compare the examples you provided:

1. HCl vs. HF:
HCl is stronger than HF because the hydrogen-chlorine bond in HCl is more polar than the hydrogen-fluorine bond in HF. Chlorine is more electronegative than fluorine, so it attracts the shared electron pair in the bond more strongly, creating a greater separation of positive and negative charges. This makes the bond more polar and the acid stronger.

2. HF vs. H2O:
HF is stronger than H2O because the hydrogen-fluorine bond is more polar than the hydrogen-oxygen bond in water. Again, fluorine is more electronegative than oxygen, resulting in a more significant separation of charges and a stronger acid.

3. H2Se vs. H2S:
H2Se is stronger than H2S because selenium is more electronegative than sulfur. As a result, the hydrogen-selenium bond is more polar than the hydrogen-sulfur bond, making the acid stronger.

So, in general, the stronger acid in a pair of binary acids is determined by the polarity of the bond between the hydrogen atom and the other atom, which is influenced by the electronegativity difference between the elements involved. The stronger the electronegativity difference, the stronger the acid.