Home > Community > Why is HNO3 more acidic than H2SO4?
Upvote

13

Downvote
+ Acids
+ Chemistry
+ Nitric acid
Posted by
Maliha Bano

Why is HNO3 more acidic than H2SO4?

Aileen Sotin  Follow

Yes, sulphuric acid (H2SO4) is a stronger acid than nitric acid (HNO3) though both are typical strong acids.

(1) When conc.H2SO4 is mixed with conc.HNO3, the latter behaves as a proton acceptor or base!

H2SO4 + HNO3 → H2NO3(+) + HSO4(-)

The result of this direct encounter between the two clearly establishes that sulphuric acid is the boss when they are forced to co-exist.

(2) Again, hot sulphuric acid quite easily displaces nitric acid from the latter’s salts (nitrates).

NaNO3 + H2SO4 (hot, concentrated) → NaHSO4 + HNO3

But, being the weaker acid between the two, nitric acid cannot displace sulphuric acid from the latter’s salts (sulphates).

More

Upvote

VOTE

Downvote
Carlos Torres  Follow

HCLO4>HCL>H2SO4>HNO3 decreasing order of acidic strength.

Hclo4 is more acidic all of the them because Oxygen is more electronegative and shows four different resonating structures.

More

Upvote

VOTE

Downvote
Christopher Proescher  Follow

To answer your question, let's look at pKa values of the acids! What is pKa?
Just like pH was invented for the hydrogen ion concentration, pKa is the scale used to deal with the dissociation of acid. The more the dissociation, the stronger the acid. This means, lower the number, the more acidic the acid.

[math]HCl[/math] = -6.3
[math]HNO_3[/math] = -1.4

So, [math]HCl[/math] is more 'acidic' than [math]HNO_3[/math].

More

Upvote

VOTE

Downvote
Charlie Perrin  Follow

H2SO4 is a stronger acid than HNO3

please upvote if it helps.

More

Upvote

VOTE

Downvote
Ashwin Adhikari  Follow

What do you mean by powerful in respect of an acid ?

HNO3 is a strong acid which dissociates completely

H3PO4 is a weak acid that dissociates only partially

In solutions with the identical molarity , there will be a higher concentration of H+ ions in the HNO3 solution than there is in the H3PO4 solution. The HNO3 will have a lower pH - it is a stronger acid.

More

Upvote

VOTE

Downvote
Barry Austern  Follow

In reasonably dilute aqueous solution they are equally strong. It's sort of like asking whether pink or white grapefruits are more grapefruity. In mixes of concentrated acids nitric is protonated to form NO2+ so sulfuric seems stronger. To really tell one should research Ka’s in an acidic solvent such as dry acetic acid or SO2.

More

Upvote

VOTE

Downvote
Curious  Follow

Hot and concentrated sulphuric acid can also gradually dissolve cupric sulphide by the following redox reaction.

CuS + 4H2SO4 = CuSO4 + 4SO2 + 4H2O

But dilute H2SO4 is non-oxidising, and so it is unable to attack the insoluble CuS effectively.

In case of nitric acid (HNO3), even the dilute acid has strong oxidising properties and so it can more easily react with the insoluble sulphide at high temperatures.

More

Upvote

VOTE

Downvote
Danu Novmanu  Follow

Let me ask you what are the similarities, sure they are both acids but they have a lot of differences.

  1. HNO3 is a protic acid and H2SO4 is a diprotic acid, this means that while HNO3 donates a single H+ H2SO4 donates 2 H+ ions.
  2. HNO3 is highly volatile as compared to H2SO4.
  3. The components are different, the molecular weights and melting point and boiling points are different.
  4. H2SO4 is dubbed the king of acids because it has a variety of reactions, while HNO3 has quite a few reactions it is not comparable to H2SO4’s

More

Upvote

VOTE

Downvote
Dennis Sardella  Follow

Hard to say because it doesn’t exist.

More

Upvote

VOTE

Downvote