Pharmaceutical Aids and Necessities Part 1

allelipraise's version from 2017-07-27 13:47

Section 1

Question Answer
Arrhenius Concept:AcidsAny substance which is capable of providing hydrogen ions (or protons H+) in aqueous solution.
Arrhenius Concept:BasesAny substance containing hydroxy groups and/or capable of providing hydroxide ion (OH-) in aqueous solution.
BrÖnsted-Lowry Concept:AcidsAny substance capable of donating a proton (H+) in a chemical reaction
BrÖnsted-Lowry Concept:BasesAny substance capable of accepting a proton (H+) in a chemical reaction
Lewis Acid-Base Concept:AcidsAny substance which can accept a share in a pair of electrons in a reaction.
Lewis Acid-Base Concept:AcidsElectron acceptor (electron seeking, electrophilic)
Lewis Acid-Base Concept:BasesAny substance that donates a pair of electrons to share with an acid in a reaction.
Lewis Acid-Base Concept:BasesElectron donor (nucleophilic species)
BrÖnsted-Lowry ConceptProtonic concept
Brönsted acid ionizes to produce a proton and the conjugate base of the acid.
Brönsted basessually neutral molecules or anions, although few cases of cations acting as proton acceptors are known.
Conjugate acid species formed when a base accepts a proton
BrÖnsted-Lowry ConceptGeneral rule: – Strong acids have weak conjugate bases and similarly, strong bases have weak conjugate acids.

Section 2

Question Answer
Pearson’s HSAB principle Further categorizes the acids and bases according to the properties of charge, size (ionic radius), polarizability, etc.
Hard AcidsElectron pair acceptors, having high positive charges, relatively small sizes and unfilled valence shell orbitals, high electronegativity and low polarizabilities.
Hard BasesHigh electronegativity, easily reduced, have stable valence shell structures, low polarizabilities.
Soft AcidsLow positive charges, relatively large sizes, and filled valence shell orbitals, low electronegativity and high polarizabilities.
Soft BasesLow electronegativity, easily oxidized, have empty low-lying orbitals and high polarizabilities.

Section 3

Question Answer
Dissociation Constant (Ka)A strong acid is an acid that loses its proton easily, while a weak acid holds its proton tenaciously.
Dissociation Constant (Ka)The conjugate base of a strong acid is a WB, whereas that of a weak acid is a strong base
Dissociation Constant (Ka)The % ionization and the ionization constant are measures of the strength of a given acid.
pHLogarithm of the reciprocal of the hydrogen ion activity (also as the negative logarithm of the hydrogen ion activity):
pHlog[1/H+] = – log[H+]
BuffersType of systems that are pairs of related chemical compounds capable of resisting large changes in the pH of a solution caused by the addition of small amounts of acid or base.
Buffer ActionAbility to resist pH changes
Buffer CapacityEfficiency to resist pH changes
Bloodstays at pH = 7.4, even when various reactions in the body produce much H+ and OH-
BloodThe buffer system in _____ is H2CO3/HCO3-
Henderson-Hasselbalch EquationpKa = – log[Ka]