 Strong and Weak Acids  Titration  Common Acid Names Textbook section 4.3

 Defined:  ACID Produces H + ions in water solution  BASE Produces OH - ions in water solution Acid Characteristics: –Sour Taste (lemon) –Change Indicators Colors (litmus blue to red)

 Strong Acids Ionize completely. HCl (aq)  H + (aq) + Cl - (aq)  The strong ACIDS are: 1. HCl 2. HBr 3. HI 4. HNO 3 5. H 2 SO 4 6. HClO 4 What are the names of these acids? Check the partner of the “H” for a hint. These must be memorized.

 Weak acids ionize partially. General formula: HB H + + B - Double arrow means reversible or it does not go to completion. The equilibrium includes both products AND reactants. Compare # of HCl ions in solution to HF ions in solution. Each w/ 1.0 M concentration.

 Strong Bases Ionize Completely  NaOH  Na + + OH -  Hydroxides are commonly strong bases. Including: LiOH KOH Ca(OH) 2 Sr(OH) 2 Ba(OH) 2

Produce OH - ions by reacting with the water. NH 3 aq + H 2 O aq   NH 4 + aq + OH - aq Pulling an H+, and leaving OH- behind. We often write water HOH, to easily keep track of this water reaction Include: ammonia NH 3 amides R-NH 2 Weak bases are weak electrolytes. The bulb will light up but it will be dim

 Mix and acid and base what happens?  The results depend upon the strength of the reactants. 3 TYPES:  1 Strong ACID - Strong BASE  2 Weak ACID – Strong BASE  3 Strong ACID – Weak BASE

 Neutralization Reaction occurs  The products are water, and an aqueous salt. (ions) Consider Nitric Acid and Sodium Hydroxide H + + NO Na + + OH -  Since they are “strong”, they fully ionize Animation of Nitric acid and Sodium Hydroxide Neutralization produces Water and a salt.

 Write the complete equation for this reaction  Identify any spectator ions and then write a net ionic equation.  2 step reaction occurs, The acid HF partially dissociates to H + + F - Then the Base NaOH, which has dissociated to produce OH - ions (plus the Na+ ions) The H+ and OH- combine to from water

The weak base gets “protonated” The strong acid is already dissociated into H + and B -. Consider ammonia and Hydrochloric Acid NH 3 + H + + Cl -  NH Cl - Methylamine and Nitric Acid CH 3 NH 2 + H +  CH 3 NH 3 +

 Poem That Makes Sense After Studying Predicting Reactions: Johnny finding life a bore, drank some H 2 SO 4. Johnny's father, an M.D., gave him CaCO 3. Johnny's neutralized, it's true, But now he's full of CO 2.

An standardized acid (known concentration) may be used to determine the unknown strength of a base. (or visa- versa) Using an indicator (solution that changes color) you can know when the added solution is exactly equal to the unknown. this is known as the EQUILVALENCE POINT.

Objective: Determine the equivalence point. Equivalence point n OH - = n H + If 25.00mL of M NaOH is needed to react with mL of HCl. What is the molarity of HCl? 1. Write the reaction 2. Use M 1 V 1 =M 2 V 2 In this case the formula could be written M OH - V OH - = M H + V H +

Arrhenius: Acids put H+ into water Bases put OH- into water Bronsted-Lowry Acids: “ADP” Acids donate protons Bases accept protons