Halogens like HCl not
2006-09-30 07:02:56 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
HF is considered weak acid because its dissociation constant is small (2x10^-4 at 25 oC). Every other hydroallogen (HCl, HBr, HI) is a strong acid, they dissociate fully in the aquatic solutions.
HF is weak because fluorine has a very small atomic radius. So the covalent bond between F and H is very strong and dissociates with great difficulty, although fluorine is very electronegative element, and the bond is very polarized.
2006-09-30 07:26:23 · answer #1 · answered by Dimos F 4 · 0⤊ 0⤋
A weak acid is an acid that does not fully ionize in solution; that is, if the acid was represented by the general formula HA, then in aqueous solution a significant amount of undissociated HA still remains.
Hydrofluoric acid is a very toxic and corrosive acid.
Perhaps confusingly, it is considered a weak acid because of its low tendency to dissociate to ions in water.
Hydrofluoric acid is notoriously known to dissolve glass by reacting with SiO2, the major component of most glasses.
2006-09-30 07:21:54 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Hydrofluoric acid is considered a weak acid only because it has a low tendency to dissociate into ions in water. However, it IS STILL highly corrosive and toxic. It has been known to dissolve glass.
*If you combine all our answers, you'll get one perfect answer. The first answer was good, but didn't exactly describe what a strong attachment to fluorine meant, even though he did mention the low ionization constant.
2006-09-30 07:08:28 · answer #3 · answered by عبد الله (ドラゴン) 5 · 0⤊ 0⤋
that's a good question. Your suitable that fluorine atoms are very electronegative. that's the reason Hydrofluoric acid is a weak acid. It does no longer dissociate one hundred% because the bond between hydrogen & fluorine atoms in the molecule is better than the different Halogen atoms. H-F Bond power = 568.2 those are all Kj/mol H-Cl = 431.9 H-Br= 366.a million H-I = 298.3 The better the bond the weaker the acid....
2016-12-04 01:45:12 · answer #4 · answered by ? 4 · 0⤊ 0⤋
It's a weak acid because it does not dissocate completely in water- some of it is always forming bak into HF. It probably has something to do with electronegativity, check a periodic table.
2006-09-30 07:07:47 · answer #5 · answered by sciguy 5 · 0⤊ 0⤋
A strong acid dissociated completely in water
HF does not as the H-F bond is too strong to be easily hydrolysed.
2006-09-30 07:07:47 · answer #6 · answered by christopher N 4 · 0⤊ 0⤋
It has a low ionization constant..... the fluorine has a stonger attachment to the hydrogen then the chlorine in HCl
2006-09-30 07:06:53 · answer #7 · answered by The Cheminator 5 · 0⤊ 0⤋