Question

How might you explain the difference between the pH values of the 0.01 M HCl (pH = 1.1) and the 0.01 M HC2H3O2 (pH = 3.6)?

HCl produces less H+.
HCl dissociates more.
HC2H3O2 produces both H+ and OH-.
HC2H3O2 produces more H+.

Answer 1

What would you say if I gave you the hint:
\(\Large \textrm{Acid dissociation constant, p}K_a\)

Answer 2

In general are all acids equally strong and how would you define a strong acid?

Answer 3

I am not sure

Answer 4

OH OK I looked up the acid dissociation constant, pKa and it explained a lot.

Answer 5

Okay then I try help you. :)
Lets set up an acid reaction:
\(\Large \textrm{HA + H}_2 \textrm{O} \rightleftharpoons \textrm{A}^- + \textrm{H}_3\textrm{O}^+ \)

This is a standard acid reaction in which a proton is being dissociated from the acid A to form \(\textrm{H}_3\textrm{O}^+\).
This reaction got an equilibrium and we now define two terms:
1) Strong acid: Is an acid that push the equilibrium to the right / fully dissociates
2) weak acid: is an acid that \(\bf partly \) push the equilibrium to the right / \( \bf partial \) dissociates.


So we now remember the definition of pH:\[pH=-\log(H_3O^+)\]
So the stronger the acid -> the more \(\textrm{H}_3\textrm{O}^+\). is produced -> pH is falling.

Answer 6

Hehe good :)

Answer 7

Strong and weak acid is a very good concept to know and also to kinda know if the molecules are strong and weak acids by knowing their structure. :)

Answer 8

For example: HCl
The acid reaction is in all its simplicity the ability to lose a proton, \( H^+\). We know that Cl is a highly electronegative element meaning it want electrons badly and thereby is pulling in the hydrogen's electron. Because of this the proton can easy dissociates cause the electron is more and more distributed at the chloride.