(11) Acid Base Equilibria Flashcards
what was arrhenius’ theory
acids: dissociates in water to give H+ ion
bases: react with H+ to give water
what does hydrogen consist of
one proton one electron
what happens when hydrogen ionises
produces a single H+ ion (bare proton)
bp has very large surface charge density (centre of +ve charge)
- protons therefore attract -ve charge
why are bare protons not found in water
bc of their small size and high charge, theyre always bonded to at least one molecule
whats the first step in hydration of a proton
formation of hydroxonium ion, H3O+
H+ + H2O —> H3O+
describe hydroxonium ions and water molecules state in aq
dynamic equilibrium
describe water bonding with ammonia
- ammonia unshared electron pair attracts proton from hydroxonium ions
- bond between proton and water weakens
- new bond formed with proton and ammonia
why is ammonia a stronger base than water
- there is competition for a proton
- bc water transferred proton to ammonia, ammonia is stronger
why is the theory of arrhenius not good
only applies to aq
what is brønsted-lowry theory
-acid is proton donor (hydrogen ion)
- base is proton acceptor (hydrogen ion)
what are we actually talking about when we say hydrogen ions in solution
hydroxonium ions
general equation for relationship between acid and corresponding base
HB <=> H+ + B-
HB = acid (proton donor)
H+ = proton
B- = base (proton acceptor)
H+ and B- form an acid-base conjugate pair (join together)
HB is the conjugate acid of B
B- is the conjugate base of HB*
base gains H+
acid loses H+
equation that shows water behaves as acid and base
H2O (acid) + H2O (base) —> H3O+ (conjugate acid) + OH- (conjugate base)
