Strong and Weak Acids
Strong and Weak Acids
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ACIDS are solutions that release HYDROGEN IONS (H⁺) in water.
They do this because they IONISE when dissolved in water. This means the molecules of the acid BREAK UP into their IONS.
For example:
These are acids that FULLY IONISE in water, meaning ALL of the acid molecules break up into IONS.
This means ALL their available H+ ions are released into the solution.
This complete ionisation leads to a HIGHER CONCENTRATION OF H⁺ IONS, which generally results in a LOWER pH.
Here are some common STRONG ACIDS and their ionising equations:
These acids PARTIALLY IONISE in water, which means only SOME of the acid molecules break up into their ions.
The incomplete release of H⁺ ions results in a LOWER CONCENTRATION OF H+ IONS, which generally results in a HIGHER pH compared to strong acids of the same concentration.
Examples of WEAK ACIDS include, ETHANOIC ACID, CITRIC ACID and CARBONIC ACID.
The MORE H+ IONS there are in a give volume of solution the MORE ACIDIC the solution is.
This means the HIGHER the H+ CONCENTRATION of an acid, the LOWER the pH. The relationship between the two is:
You can extend this relationship to bigger changes in pH and H+ concentrations:
Let's try an example using this relationship:
Don’t get confused between the strength of an acid and its concentration:
Concentration and strength are INDEPENDENT of each other, meaning you can have:
ACIDS are solutions that release HYDROGEN IONS (H⁺) in water.
They do this because they IONISE when dissolved in water. This means the molecules of the acid BREAK UP into their IONS.
For example:
These are acids that FULLY IONISE in water, meaning ALL of the acid molecules break up into IONS.
This means ALL their available H+ ions are released into the solution.
This complete ionisation leads to a HIGHER CONCENTRATION OF H⁺ IONS, which generally results in a LOWER pH.
Here are some common STRONG ACIDS and their ionising equations:
These acids PARTIALLY IONISE in water, which means only SOME of the acid molecules break up into their ions.
The incomplete release of H⁺ ions results in a LOWER CONCENTRATION OF H+ IONS, which generally results in a HIGHER pH compared to strong acids of the same concentration.
Examples of WEAK ACIDS include, ETHANOIC ACID, CITRIC ACID and CARBONIC ACID.
The MORE H+ IONS there are in a give volume of solution the MORE ACIDIC the solution is.
This means the HIGHER the H+ CONCENTRATION of an acid, the LOWER the pH. The relationship between the two is:
You can extend this relationship to bigger changes in pH and H+ concentrations:
Let's try an example using this relationship:
Don’t get confused between the strength of an acid and its concentration:
Concentration and strength are INDEPENDENT of each other, meaning you can have:
