Acid Strength

Concept #1: Strong acids are strong electrolytes that completely ionize while weak acids are weak electrolytes that partially ionize. 

Concept #2: When looking at the strength of binary acids we look at the electronegativity of the nonmetal or the atomic size of the nonmetal. 

Example #1: Which is the weakest acid from the following?

a) H₂S                          b) HF                            c) H₂Te             d) All would have the same acid strength. 

Example #2: Which of the following acids would be classified as the strongest?

a) CH₄                          b) NH₃                          c) H₂O                          d) HF                            e) PH₃

Concept #3: The strength of oxyacids is based on the number of oxygens or the electronegativity of the nonmetal excluding oxygen. 

Concept #4: When comparing the strengths of oxyacids we can rely on two important rules. 

Concept #5: Oxalic acid, iodic acid and amphoteric species are the exceptions in determining the strength of oxyacids. 

Example #3: Rank the following oxyacids in terms of increasing acidity.

a) HNO₃                                     b) HC₇H₅O₂                                                 c) H₂CO₃                                                      d) HClO₃