acids and bases Flashcards
what is an acid?
a substance that ionises or dissociates in water to produce hydrogen ions
what kind of taste do acids have?
sour taste
what color does acid turn litmus paper?
turn blue litmus paper red
what color does acid turn universal indicator?
red/orange
what pH does acid have?
less than 7
why can acids conduct electricity?
there are mobile ions (H+) in the acid
what is an alkali?
a soluble base that ionises in water to form hydroxide ions
what is a base?
substances that react with acids to form salt and water only
what kind of taste do alkalis have?
bitter taste and feel soapy
what colour do alkalis turn litmus paper?
turn red litmus paper blue
what colour do alkalis turn universal indicator?
blue or violet
what pH do alkalis have?
greater than 7
why can alkalis conduct electricity?
the presence of mobile ions (OH-) to act as mobile charge carriers
how do acids react with bases in a neutralisation reaction?
acid + base -> salt + water
how do acids react with carbonates?
acid + carbonate -> salt + water + carbon dioxide
how do acids react with metals?
acid + metal (reactive) -> salt + hydrogen
why do acids only act like acids when it is dissolved in water?
when acid is dissolved in water, it dissociates to form hydrogen ions and behaves as an actual acid
what does a concentration of an acid refer to?
the number of moles of acid dissolved in each litre/dm^3 of water
what does the strength of an acid refer to?
extent of dissociation or ionisation of the acid molecule into ions when dissolved in water
what does the basicity of an acid refer to?
refers to the number of H atoms in one molecule of acid that can be replaced by a metal
how do alkalis/bases react with acids?
alkali/base + acid -> salt + water
how do alkalis/bases react with ammonium salts?
alkali + ammonium salt -> salt + water + ammonia
how do alkalis react with solutions of salts of many metals?
alkali + salt solution of metal A -> metal A hydroxide + salt of alkali
what does the strength of an alkali depend on?
degree/extent of ionization
what are acidic oxides?
oxides of non-metals and form acids in water
how do acidic oxides react with alkalis?
acidic oxide + alkalis +-> salt + water
what are basic oxides?
oxides of metals that are mostly insoluble in water while those that dissolve in water form alkalis
how do basic oxides react with acids?
basic oxide + acid -> salt + water
what are amphoteric oxides?
metallic oxides that can behave as acidic oxides or basic oxides and are insoluble in water
how do amphoteric oxides react with both acids and bases?
amphoteric oxide + acid/base -> salt + water
what are neutral oxides?
non-metallic oxides that exhibit neither basic nor acidic properties and are insoluble in water
how do neutral oxides with both acids and alkalis?
they do not react with acids and alkalis
which oxides are soluble in water to form alkalis?
group I oxides, calcium oxide, barium oxide
what oxides are formed by metals?
basic oxide, amphoteric oxide
what oxides are formed by non-metals?
neutral oxide, acidic oxide
what is the solubility of amphoteric oxides?
insoluble in water
