Acid/Base Flashcards
(27 cards)
If a molecule forms a very stable conjugate base when protonated, will its pKa be low or high?
Low
If a molecule forms a very unstable conjugate base when deprotonated, will its pKa be low or high?
High
Rank the following protons from MOST to LEAST acidic
FH, BrH, ClH, IH
F, Cl, Br, I
Rank the following protons from LEAST to MOST acidic
FH, BrH, ClH, IH
I, Br, Cl, F
Which proton is LESS acidic?
OH or SH
OH
Which proton is more acidic?
OH or SH
SH
Are amines strong bases or weak bases?
Weak bases
Are carboxylic acids strong acids or weak acids?
Weak acids
How are Ka and pKa mathematically related?
Inversely
Low Ka –> high pKa
High pKa –> low Ka
Acid-base reactions will favor the protonation of the…
…weaker acid
Side with the larger pKa is favored
In a reaction, the reactants side has a smaller pKa and the products side has a larger pKa. Which side is more favored?
Products
The side with the larger pKa is favored
In a reaction, the reactants side has a larger pKa and the products side has a smaller pKa. Which side is more favored?
Reactants
The side with the larger pKa is favored
Which has a larger dipole, O=N or O=S?
O=S
Bronstead-Lowry acid
Proton donor
Bronstead-Lowry base
Proton acceptor
Lewis acid
Electrophile, accepts a pair of electrons
Lewis base
Nucleophile, region of electron density, donates a pair of electrons
What happens in a Lewis acid/base reaction?
Nucleophile (base) attacks the electrophile (acid)
The nucleophile uses its highest occupied molecular orbital and the electrophile uses its lowest unoccupied molecular orbital
Forms a covalent bond between the two species
What kinds of molecules can be lewis acids?
All cations
Anything with an incomplete octet
pKa for strong acids
Low
pKa for weak bases
Low
pKa for weak acids
High
pKa for strong bases
High, greater than 11
Larger pKa
Weaker acids, stronger conjugate bases
