When an acid and base undergo a neutralization reaction they form ions, which can create acidic, basic or neutral solutions.
Cations (positive ions) can create either acidic or neutral solutions.
Concept #1: Transition Metal Cations and Acidity.
If the transition metal within an ionic compound has a charge of +2 or higher then it creates an acidic solution. If it’s less than +2 then it creates a neutral solution and is classified as a non-significant ion.
Concept #2: Main Group Metal Cations and Acidity.
If the main group metal within an ionic compound has a charge of +3 or higher then it creates an acidic solution. If it’s less than +3 then it creates a neutral solution and is classified as a non-significant ion.
Concept #3: Positive Amines and Acidity.
Amines are compounds with only nitrogen or hydrogen (i,e. NH3) or with carbon, nitrogen and hydrogen (i,e. CH3NH2). Positive amines within compounds create acidic solutions.
Anions (negative ions) can create either basic or neutral solutions.
Concept #4: Anions and Basicity.
To determine if an anion is basic or neutral you must add an H+ to it. If adding an H+ creates a weak acid then your negative ion is basic, but if adding an H+ creates a strong acid then your negative ion is neutral.
Example #1: Determine if the following compound will create an acidic, basic or neutral solution: NaOCl
Example #2: Determine if the following compound will create an acidic, basic or neutral solution: PbCl4
Practice: Determine if each of the following compounds will create an acidic, basic or neutral solution.
a) LiC2H3O2 b) C6H5NH3Br
Practice: Determine if each of the following compounds will create an acidic, basic or neutral solution.
a) Co(HSO4)2 b) Sr(HSO3)2
Practice: Determine if each of the following compounds will create an acidic, basic or neutral solution.
Example #3: Determine whether each compound will become more soluble in an acidic solution.
a) NaBr b) LiCl c) KIO
Example #4: Determine the pH of a 0.50 M NH4Cl solution. The Kb of NH3 is 1.75 x 10-5.
Practice: Determine the pH of a 0.55 M NaCN solution. The Ka of hydrocyanic acid, HCN, is 4.9 x 10-10.