Why H2SO4 is less stronger than HClO4?

Answer 1

That's still I have some confusion. You can never tell HCl is Stronger than H2SO4, because H2SO4 can donate two protons in reaction. So H2SO4 is seems stronger.

But in another way in water HCl has more HIGHER Ka value. So in that sense we can tell:

HCl is stronger.Added:

The number of protons in an acid molecule doesn't tell you about its strength. Look for instance at phosphoric acid: H3PO4 even has three protons (H+) but they are all three to be considered as weak!

The strength of an acid is ONLY determined by Ka (acid equilibrium constant) and called weak if Ka<1, or strong if Ka>1. For mono-protic acids like HCl, it means that more than about 50% to 65% is protolysed (has split of protons).

The pH however is SLIGHTLY determined by the number of protons (being 1 or 2) but only for strong acids: pH is at maximum 0.3 pH units lower for a strong 'double proton' acid compared with a 'single proton' acid. ( -log10 of 2 equals -0.3). With weak acids the second protolysis can mostly be neglected.

Answer 2

When NH4OH reacts with HCl it gives dense white fumes.

NH4OH + HCl --> NH4Cl + H2O

dense white fumes

When H2SO4 reacts with HCl it gives a ppt rather than dense white fumes

NH4OH + HSO4--> (NH4)2SO4 +H2O

Answer 3

acidity of Perchloric acid is greater than Sulphuric due to the resonance stability of Perchlorate ion or you can say resonance delocolization.this leads to greater stability.resonance delocalization of pi-electrons means that in perchlorate ion,the chlorine atom is completely covered by its 4 oxygen atoms and there is no lone pair of electrons on the chlorine atom.charge of the ion is completely and evenly spread over all 4 oxygen atom.this leads to a well-balanced resonance stabilized structure. and as you know that a strong acid dissociates or ionizes completely or to a greater extent.as the stability of anion or conjugate base is greater;this leads to the greater strength of perchloric acid-

a comparison will make the idea more clearer;

1-pKa of HClO4 is 10 and pka of H2SO4 IS 1.9

2-any d/f in bond strength is due 2 d/f b/w Cl and S

WE CAN ALSO ANSWER that the electronegativity of the conjugate base of sulfuric acid is greater so it tend to attract the hydrogen ion more and less likely to release it,consequently decreasing its strength

Answer 4

Yes, nitric acid is very strong, hydrogen sulfide is very weak (pKa = 6.9).

Answer 5

h2s04 is stronger

Answer 6

I suppose that HCl is stronger.

Answer 7

Yes