Some common acids include sulfuric acid (H2SO4), hydrochloric acid (HCl), nitric acid (HNO3) and ethanoic acid (CH3COOH).
Common bases include group 1 and 2 metal hydroxides (NaOH, KOH, LiOH, Ba(OH)2, Ca(OH)2).
Metal oxides are usually basic and non-metal oxides are usually acidic.
Concentration of a solution is usually measured in mol/dm3, where the concentration can be calculated from the number of moles divided by the volume.
Acids
An acid dissociates to give hydrogen ions (H+) in aqueous solution.
In a strong acid, the molecule completely dissociates in aqueous solution, whereas a weak acid only partially dissociates.
Neutralization occurs in the reaction between an acid and a base, where a neutral solution is created.
H+(aq) + OH-(aq) –> H2O(l)
pH scale
The pH scale measures the concentration of hydrogen ions in a solution.
A pH of 7 is neutral, below 7 is acidic and above 7 is basic.
The pH scale is a logarithmic scale where each pH step increase is a change of 10x the concentration of hydrogen ions.
pH can be calculated from pH = -log [H+]
Measuring pH
A pH meter can be used to measure pH.
Indicators are substance that change colour depending on the pH.
Some common indicators include universal indicator (which is a mix of different substances), bromothymol blue, phenolphthalein and litmus.
Reactions of acids
Acids react with bases to give a metal salt and water.
Acids react with carbonates and hydrogen carbonates to give a metal salt, carbon dioxide and water.
Acids react with metals above hydrogen in the reactivity series (including zinc, magnesium and iron) to give a metal salt and hydrogen.
Titration
Acid-base titration is a method for measuring the concentration of an acid using a base of known concentration (or vice versa).
A pipette and burette can be used to make precise measurements in a titration.
The equivalence point is where the volume of acid and base added is just right so that neither is in excess.
For a strong acid and base, the equivalence point will be at neutral pH.
To calculate the concentration from titration data, the formula C1V1 = C2V2 can be used.
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