Acids and Bases Flashcards
Properties of acids:
- Turns litmus paper red
- Corrosive
- Conducts electricity
- Tastes sour
- Reacts with bases
- pH of <7
Properties of bases:
- Turns litmus paper blue
- Caustic and slippery
- Conducts electricity
- Tastes bitter
- Reacts with acids
- pH > 7
The Arrhenius model:
- Acids are substances that ionises in water to produce a hydrogen ion/proton.
- Bases are substances that dissociate in water to form hydroxide ions
What Arrhenius Didnt know?
Didnt know that H+ ions do not exist freely in water, but rather bond co-ordinate covalently to form hydronium ion.
-H+(aq) + H20(l) ->H30(aq)
Polyprotic Acids:
Monoprotic - Acid that only produces one H+
Diprotic - Acid that produces 2 H+
Triprotic - Acid that produces 3 H+
Strong Acid/base:
Is a substance that completely ionises/dissociates in water. (–>)
Weak acid/base:
A substance that partially ionises/dissociates in water and therefore some reactants are still present as molecules. (<–>)
Strong Acids:
-HCl, HNO3, H2SO4
Strong Bases:
-NaOH, KOH, Ba(OH)2
Weak Bases:
-NH4, CH2NH2 (Methyl amine)
Weak Acids:
-CH3COOH, H2CO3(Carbonic), H3PO4(Phosphoric)
Strength Vs Concentration:
The strength of an acid/base is unrelated to the concentration of it.
Limitations of Arrhenius:
- Does not explain how CO2 and SO2 is an acid even though no hydrogen atoms.
- NH4 and NaCO3 form basic solutions when mixed with water even though no hydroxide groups.
Bron Sted Lowry Model:
It explains Arrhenius’s limitations via process of hydrolysis.
- Acids are defined as proton donors and bases are proton acceptors.
Universal indicator:
An indicator is a material that is altered by the presence of an acid/base.
- UN IND Is a mixture of several different indicators and gives a good range of colours when tested with acids and bases.
