MEETING 5. ACID-BASE TITRATION

- WHAT IS TITRATION? - WHY ACID-BASE TITRATION IS CALLED NEUTRALIZATION TITRATION? - WHAT IS ACIDIMETRIC TITRATION? - WHAT IS ALKALIMETRIC TITRATION? - WHAT IS THE PRINCIPLE OF REACTION?

Titration Strong acid Weak acid Strong base Weak base

Principle reaction:  Involve the change of [H + ] and [OH - ]  Involve the change of pH.  What is pH?  What is pH of 100 mL HCl 0,1 M?  What is pH of 100 mL NaOH 0,1 M?  Is pH of 100 mL HCl 0,1 M similar with pH of 100 mL CH 3 COOH 0,1 M

Curve of Acid-base Titration HCl + NaOH  NaCl + H 2 O Reaksi ionnya : H + + OH -  H 2 O Strong acid + Strong Base Example : HCl + NaOH  NaCl + H 2 O Ionic reaction : H + + OH -  H 2 O

What is the pH of titration?  10 mL HCl 0,1 M + 0 mL NaOH ?  10 mL HCl 0,1 M + 5 mL NaOH 0,1 M?  10 mL HCl 0,1 M + 10 mL NaOH 0,1 M?  10 mL HCl 0,1 M + 20 mL NaOH 0,1 M?

HOW ABOUT THIS? 10 mL HCl 0,1 M + 0 mL NH 4 OH ? 10 mL HCl 0,1 M + 5 mL NH 4 OH 0,1 M? 10 mL HCl 0,1 M + 10 mL NH 4 OH 0,1 M? 10 mL HCl 0,1 M + 20 mL NH 4 OH 0,1 M?

Indicator in Acid-base titration  The color change should be as near as possible to equivalent point  In Fact: it is very difficult end point of titration  End Point ~ Equivalent Point  How can we choose the indicator?

pH range of some indicators IndikatorDaerah pH Warna asam Warna basa Pelarut Thimol biru1,2 - 2,8MerahKuningAir Metil kuning2,9 – 4,0MerahKuningEtanol 95% Metil jingga3,1 – 4,4MerahKuning jingga Air Metil merah4,2 – 6,2MerahKuningAir Bromtimol biru6,0 – 7,6KuningBiruAir Phenolphtalein8,0 – 9,8Tak berwarna Merah- ungu Etanol 70%

Contoh Perubahan Warna Indikator Asam-basa Example: The color change of Acid-Base Indicator

Universal Indicator