How to find the relative strength of acids. Pls answer.
Answers
Explanation:
The Bronsted-Lowry theory considers the proton-transfer reactions between conjugate acid-base pairs.
Such acid-base reactions can be seen as a competition between species for hydrogen ions.
From this point of view, we can order acids by their relative strength as hydrogen ion donors.
The stronger acids are those that lose their hydrogen ions more easily than other acids.
Similarly, the stronger bases are those that hold onto hydrogen ions more strongly than other bases.
If an acid loses its H+, the resulting anion is in a position to reaccept a proton, making it a Brønsted-Lowry base.
It is logical to assume that if an acid is considered strong, its conjugate base (i.e. its anion) would be weak, since it is unlikely to accept a hydrogen ion.
5.2.6.1 Which acid is stronger?
The position of an acid-base equilibrium will depend on the relative strengths of the species involved.
HNO3 (aq) + H2O (l) NO3- (aq) + H3O+ (aq)
acid base base acid
In the above system, we have two opposing Brønsted- Lowry acid-base reactions.
HNO3 is a much stronger acid than H3O+, so the equilibrium lies far to the right.
5.2.6.2 Molecular Structure and Acid Strength
Two factors are important in determining the relative acid strengths.
One factor is the polarity of the bond to which the hydrogen atom is attached.
The H atom will have a partial positive charge.