1. pH
INDICATORS
in chemistry and everyday life

2. pH SUMMARY INDICATORS SUMMARY 1. 2. 3. 4. 5. 6. Introduction12
SUMMARY 1. 2. 3. 4. 5. 6.
Introduction
Definition of pH
Acids and bases
Bromothymol blue
Natural indicators
pH paper
SUMMARY

3. pH INTRODUCTION INDICATORS3 12
INTRODUCTION
A pH indicator is a halochromic chemical compound that is added in small amounts to a solution in order to determinate easily the pH (acidity or alkalinity) of the solution.

4. pH DEFINITION OF pH INDICATORS4 12
pH is a mathematic tool used in chemistry to measure acidity of a solution
mathematic definition for diluted solutions :
DEFINITION OF pH
usual pH range : 0-14

5. pH ACIDS & BASES INDICATORS5 12
pH indicators exist under severals forms of acide-base couples :
InH in acidic solutions (1st colour)
In- in basic solutions (2nd colour)
-> So, the colour of the solution can give us informations about acidity of the solution
ACIDS & BASES

6. pH
INDICATORS 6 12
ACIDS & BASES

7. pH BROMOTHYMOL BLUE INDICATORS7 12
Bromothymol blue is the most famous coloured indicator
BROMOTHYMOL BLUE

8. pH BROMOTHYMOL BLUE INDICATORS 8 12 A : acid form of BBT
B : basic form of BBT
C : pH in transition range of BBT

9. pH NATURAL INDICATORS INDICATORS9 12
We can find a lot of natural indicators in the nature :
Red cabbage (red–pink–violet–blue–green–yellow)
Turmeric / Curry (yellow-orange-brown)
Tea (yellow-brown)
Rose petals (blue-pink)
Artichoke (colorless-yellow) …
NATURAL INDICATORS

10. pH
INDICATORS 10 12
pH paper (Hydrion Paper) is a paper which contains a Universal Indicator
"Universal Indicator" means severals indicators mixed in order to emit a different color for each pH value
pH PAPER
acidic basic
pH paper is red in acid solutions and purple in basic solutions

11. Thank you for having listened us…pH
INDICATORS 11 12
Thank you for having listened us…
pH INDICATORS