Acids/Bases Flashcards
bicarbonate
base HCO3-
when added to something that is acidic, will increase pH to become more basic because HCO3- consumes H+
H+ + HCO3- H2CO3 H2O + CO2
ksp
solubility product constant
the products are multiplied together. If that concentration exceeds the ksp, they will also form a precipitate because ksp represents the limit of solubility. Everything under ksp value will be dissolved, everything over becomes solid
How does the stability of the conjugate base affect acidity?
conjugate bases made from smaller halogens will be less stables because a smaller radius has less surface area to spread out the charge (thus stabilize)
therefore while fluorine is the most electronegative, it will form a short, strong bond with H that is not acidic (wants to keep H)
What determines acidity of functional group?
more electronegative atoms are more acidic
ability to stabilize negative charge through charge distribution (atom size) or delocalization (resonance)
more acidic protons will be the first to deprotonate as pH increases
What is more acidic alkene, alkane, or ketone?
ketones are less acidic than alcohols, but more acidic than hydrocarbons. The negative charge in the conjugate base of a ketone is delocalized by resonance across the alpha carbon and carbonyl oxygen atoms, which helps stabilize the charge
alkene proteins (sp2 C-H) are more acidic than alkane proteins (sp3 C-H)
What is more acidic, primary or secondary alcohol?
a primary alcohol is more acidic which contributes to their enhanced ability to react because deprotonation by a base makes the alcohol a better nucleophile
nucleophile
Needs a New Boy
- super negative and has a lot of baggage (electrons)
- looking for positive charge to balance her out
- she is a lewis base because will provide electrons to the positive electrophile
electrophile
Electron loving
positive - wants to accept electrons
Lewis acid
How do acids affect nucleophiles?
nucleophiles are out looking for protons to make her happy because she is so negative.
acids come along and donate their H+ to nucleophile which is a bronsted base (accepts protons)
because already has a proton, will not actively search for more, reducing the nucleophilicity of the molecule
indicators
determine endpoint by changing color during titration to signal close to equivalence point (when the acid and base are equal amounts)
one color represents low pH and another color represents high pH
buffers
region that will not have a large change in pH
weak acid + conjugate base or weak base + conjugate acid (or salt)
need weak acid or base so it doesn’t completely dissociate. acids donate protons and bases accept them so work together to resist changes in pH
buffering zones are horizontal on a titration curve - point of inflection
buffering zone = 1/2 [weak acid/base]
NH3
ammonium
weak base
strong acids
HClO4 HI HBr H2SO4 HCl HNO3 H3O+ or H+
perchloric acid
HClO4
strong acid
hydrochloric acid
HCl
strong acid
sulfuric acid
H2SO4
strong acid
nitric acid
HNO3
strong acid
acidic in nature
the more oxidated something is, the more acidic
ex: CO2 is surrounded by oxygen and is like breaking pure acid
strong bases
LiOH NaOH KOH Ca(OH)2 Ba(OH)2 Sr(OH)2 CsOH RbOH
strong bases completely dissociate in solutions because the conjugate acid cation is very stable
weak acids
HCOOH (formic acid) CH3COOH (acetic acid) HF (hydrofluoric acid) HCN (cyanide) H2S (hydrogen sulfide) H2O (water)
weak bases
NH3 (ammonium) NR3 (amine) C5H5N (pyridine) NH4OH (ammonium hydroxide) H2O (water)
neutralization
acid + base –> salt + water
equivalence point
vertical line where [base]=[acid] - neutralized
amount of equivalence points is dependent on number of acidic protons (H+) - polyprotic acids have multiple pKas
strong base + strong acid
equivalence point is pH 7
strong base + weak acid
equivalence point at higher pH than 7
strong acid + weak base
equivalence point lower than pH 7
titration
technique to determine the concentration of an unknown solution
use a known concentration and slowly add to unknown solution with known volume and use indicator to see change
polyprotic acids
have more than one acidic proton
the number of acidic protons will be the number of equivalence points
adding strong base will neutralize and remove protons in stepwise fashion
How to tell acidic protons
acidic protons are attached to functional groups with low pKa values
acidic --> basic H-X R-H-O-H+ R-NH3+ carboxylic acid phenol alcohol SP amine SP2 SP3
look for protons on electronegative atoms first –> O, N, S
the most stable conjugate base will be
the strongest acid
oxyacid
acid that contains a hydrogen, oxygen, and another element
HClO
dissolves in water and creates acidic solution
ex: HClO + H2O –> H30+ + ClO-
oxides
oxygen and another element
ex: SO2
arrhenius acid
H+ donor
HA –> H+ + A-
arrhenius base
OH- donor
BOH –> B+ + OH-
Bronsted-Lowry acid
H+ donor
Bronsted-Lowry base
H+ acceptor
Lewis acid
electron acceptor aka electrophile
Lewis base
electron donor aka nucleophile
water as an acid or base
water is amphoteric - can act as either acid or base
will act a certain way depending on conditions
in basic conditions acts a s a base
ionization
complete loss of electrons
left with just an ion
M –> M+ + e-
NO2-
nitrite
NO3-
nitrate
NO4-
peroxynitrate
NO
nitroxide
SO3^(2-)
sulfite
SO4^(2-)
sulfate
PO4(3-)
phosphate
PO3(3-)
phosphite
ClO3-
chlorate
ClO2-
chlorite
HCO3-
bicarbonate
bi = single Hydrogen atom
HSO4-
bisulfate
H2PO4-
dihydrogen phosphate
di = two hydrogen atoms
ferrous
Fe2+
ous = lower charge for metal
ferric
Fe3+
ic = higher charge for metal
neutralization
acid + base –> salt + H20
can figure out how much is needed by using NacidVacid=NbaseVbase
N= normalities = number of grams/volume
V=volume
so this can be thought of as moles acid = moles base
What makes a strong Lewis acid?
smaller ionic radius and strong positive charge
Why is the conjugate base a better nucleophile than the acid?
because the conjugate base has more electron density due to the negative charge
