Acids Bases And Salts Flashcards
Litmus color acid
Red
Litmus color alkali
Blue
Phenolphthalein alkali
Pink
Phenolphthalein acid
Colourless
Methyl orange acid
Red
Methyl orange alkali
Yellow
Mash reaction
Metal + acid = Salt + hydrogen
This only works for metals above hydrogen in the reactivity series . Reaction gets slower as reactivity decreases
Magnesium and zinc salts are colourless
Iron salts are very pale
Why does aluminium not react
Protected by a layer of aluminium oxide
OASW
Acid + metal oxide = Salt and water
CAWCS
Metal Carbonate + acid = Salt + water + carbon dioxide
Why does calcium carbonate and sulphuric acid not react
Because the reaction occurs initially but forms a layer of insoluble calcium sulphate Around calcium carbonate . The insoluble layer protects the carbonate from further reaction with the acid
BAWS
Base (metal hydroxide) + acid = Salt and water
What are acids
Substances which dissolve in water to form the H+ aqueous ion
Acids only behave as acids when aqueous
What are bases
Substances which react with acids ( combine which h+ ions )
E.g metal oxides , carbonates , hydroxide
What are alkalis
Bases which dissolve in water to form the (OH) - aqueous ion
Most are soluble metal hydroxides