CH. 15 Acid- Base equilibrium

Acids

-Sour taste

-Electrolytes (i.e. conduct electricity)

- Corrosive to metals

-React with active metals to yield hydrogen gas.with Al, Zn or Fe but not Cu, Ag or Au

-Change litmus (vegetable dye) from blue to red.

-Destroy the properties of bases, forming ionic salts.

bases

-bitter taste

-electrolytes i.e conduct electricity

-slippery feel

-restore color of litmus paper to blue

-destroy properties of acids, forming ionic salts

Arrhenius theory

acid- a substance that produces H+ on dissolution in water

base- a substance that produces OH- on dissolution in water

limitations of Arrhenius Theory

-acid-base reactions only limited to aqueous solutions

-Ammonia, NH3 has properties of a base, but its chemical formula doesn’t have an -OH

-Na2CO3 forms a basic solution in water

-CO2 dissolves in water to give an acidic solution

Bronsted-Lowry Theory

acid: a substance that can act as a proton H+ donor

-The acid has an ionizable H attached to an electronegative atom

base: a substance that can act as a proton acceptor

-the base has an electron pair that can form a bond with the donated H+

polyprotic acid

a substance which can donate more than one proton

polyprotic base

a substance which can accept more than one proton

Lewis Theory

-a lewis base is an electron pair donor

-a lewis acid is an electron pair acceptor

acid ionization

reaction involving the transfer of a proton from an acid to water, yielding hydronium ions and the conjugate base of the acid

acid ionization constant (K_a)

equilibrium constant for an acid ionization reaction

-the stronger an acid, the further its equilibrium constant lies to the right the larger the acids equilibrium constant

-the more completely the acid disassociates into its conjugate base and a proton

-product favored, more H3O +

acidic

a solution in which [H₃O⁺] > [OH⁻]

base ionization

reaction involving the transfer of a proton from water to a base, yielding hydroxide ions and the conjugate acid of the base

• the water becomes OH-, and forms a conjugate acid

base ionization constant (K_b)

equilibrium constant for a base ionization reaction

-the larger the bases equilibrium constant, the more likely the base is to accept a proton ( forming the bases conjugate acid)

basic

a solution in which [H₃O⁺] < [OH⁻]

conjugate acid

substance formed when a base gains a proton

conjugate base

substance formed when an acid loses a proton

conjugate base pairs

-species whose formulas differ by only one proton

strong acid

• almost completely dissociates in water

• equilibrium lies far to the right

• Ka is very large

• completely ionizes in water

• strong electrolyte

• negligible amounts of un-ionized HA molecules in solution

• has a weak conjugate base(poor H+ acceptor)

• HA initial= H30+ equilibrium

strong bases

• essentially dissociated in water

• its equilibrium lies far to the right

• strong electrolyte(soluble ionic compound)

• negligible amounts of un-ionized MOH formula units in solution

• the cation of a strong base does not accept H+

  • MOH original= OH- equilibrium

weak acids/bases

• partially ionizes in water

• the solution has both ionized and non-ionized species

amphoteric

• water

• capable of acting as an acid or base

• Water can react with itself in an acid-base reaction : auto-ionization of water

oxyacid

ternary compound with acidic properties, molecules of which contain a central nonmetallic atom bonded to one or more O atoms, at least one of which is bonded to an ionizable H atom

percent ionization

ratio of the concentration of ionized acid to initial acid concentration expressed as a percentage

binary acid

contains hydrogen and another element