Acids, Bases & Salts Flashcards
What is an Arrhenius acid?
A substance that ionises in water to produce hydrogen ions
What is an Arrhenius base?
A substances that ionises in water to produce hydroxide ions
Limitations of Arrhenius theory (2)
It does not explain reactions that don’t involve water
It does not explain how ammonia produces hydroxide ions in water
Bronsted-Lowry acid
A substance that can donate a proton
Cue: HCl can donate H+
Bronsted-Lowry base
A substance that can accept a proton
Conjugate acids/bases
BL acid becomes conjugate base
BL base becomes conjugate acid
Limitation of Bronsted-Lowry theory
Does not explain reactions that do not involve hydrogen
Lewis acid
A substance that accepts an electron pair
Lewis base
A substance that donates an electron pair
Limitation of Lewis theory
Cannot explain reactions that do not involve dative bonding
What is pH?
A measure of the amount of free hydrogen or hydroxide ions thus reflecting the acidity or alkalinity of a solution
What is the basicity of an acid?
The number of moles of hydrogen ions produced when one mole of the acid molecules dissolve in water
Relationship between base & alkali
Alkalis are soluble bases
AKA soluble metal oxides & hydroxides
What are neutral oxides?
Some non-metallic oxides
E.g. H2O, CO, NO
What are acidic oxides?
Most non-metallic oxides
E.g. SO2, NO2, CO2
What are basic oxides?
All metallic oxides
E.g. CaO, K2O, MgO, CuO
What are amphoteric oxides?
Al2O3, ZnO, PbO
Definition of a salt
An ionic compound consisting of a cation and an anion
Preparing an insoluble salt
Use precipitation
2 soluble salts –> Insoluble salt
Acid + reactive metal –>
Salt + hydrogen
Acid + carbonate/hydrogen carbonate –>
Salt + water + carbon dioxide
Acid + metal oxides/hydroxides –>
Salt + water
Effect of acids on litmus paper
Blue –> Red
Effect of alkalis on litmus paper
Red –> Blue
Alkalis + ammonium salts –>
Salt + water + ammonia
Alkalis + salt –>
Salt + metal hydroxide
Preparing a soluble salt
- Acid with insoluble less reactive metal/base/carbonate
2. Acid with alkali titration (for more reactive metals)
What salts are prepared by titration?
Sodium, potassium, ammonium salts
How to prepare ammonium salt?
Ammonium compound + alkali