Chemistry 121 (Amar) - Fall, 2007 - Dr. Amar 

Acids and Bases
(©2007, François G. Amar, All rights reserved) 
The Strong Acids (see Table 4.2 in BLB)

The Strong Bases (see Table 4.2 in BLB)

Group 1A metal hydroxides (LiOH, NaOH, KOH, RbOH, and CsOH)

Group 2A metal hydroxides [Ca(OH)2, Sr(OH)2, Ba(OH)2]

(Note that since magnesium hydroxide is insoluble in water, it is not listed here)

Bronsted-Lowry Definition of Acids and Bases

In particular because of the basicity of many compounds that do not directly produce hydroxide ions, the Bronsted-Lowry concept of acids and bases extends the concept of base to include more classes of compounds. According to Bronsted and Lowry,

An acid is a compound with a tendency to lose or donate protons and a base is compound that can accept protons.

In particular, metal oxides act as bases and weak bases such as ammonia don't fit into the Arrhenius definition

metal oxide reaction with an acid: K2O (s) + 2 HCl (aq) --> 2 KCl (aq) + H2O (see problems 4.42 and 4.44)

and

ammonia accepts a proton from water to form hydroxide ion: NH3 (aq) + H2O (l) NH4+ (aq) + OH- (aq)

Weak acids

Acetic acid, is the template for all carboxylic acids: H3C-COOH

The acid is in equilibrium with its dissociated ions and the equilibrium is shifted

quite far to the neutral molecular compound:

H3C-COOH (aq) H+ (aq) + H3C-COO-

Some demonstrations

The following animation (taken from the BLB CD-ROM) illustrates that CO2 behaves as an acid in water:

(If the movie fails to load you may need a Quicktime Plugin)

The following animation (taken from the BLB CD-ROM) illustrates that solid MgOH)2 is insoluble in water but can be dissolved in acid.

(If the movie fails to load you may need a Quicktime Plugin)

 

 

Titrations and quantitive use of balanced reactions

Above the line: (molarity) and (volume)

Balanced chemical equation

Below the line: moles

moles = (molarity)x(volume) or volume = (moles)/(molarity)

 

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