Titration and Indicators Flashcards
a paper that has been dipped in a substance that will undergo a color change when it is dipped in either an acid or a base
litmus paper
red litmus paper turns blue = basic
blue litmus turns red = acid
common garden plant with flowers that come in many colors depending on the pH of the soil.
HYDRANGEA
blue flowers = SOIL IS ACIDIC
creamy white flowers = NEUTRAL
pink =BASIC
indicator that is produced from a substance that is naturally occurring or is itself a naturally occurring substance
NATURAL INDICATOR
Red beets, blueberries, and cranberries
are compounds created in a chemistry lab
SYNTHETIC INDICATORS
phenolphthalein
acid donates a proton and a
Bronsted-Lowry base accepts a proton
Bronsted-Lowry
two requirements for a substance to function as an acidbase indicator
- equilibrium affected by hydrogen ion concentration
- Two forms of the compound on opposite sides of the equilibrium must have different colors
the equilibrium between the protonated form and the anionic form is controlled by ———, SINCE THE INDICATOR IS A WEAK ACID.
HYDROGEN ION CONCENTRATION
If the pH of the solution is 4.8, what would be the color of the solution if the following indicators were added?
(a) Universal indicator
(b) Bromocresol Green
(c) Phenol red
(a) Universal indicator = Orange to orange-yellow (see table 2)
(b) Bromocresol Green = green (midway pH = 4.6)
(c) Phenol red = yellow
Phenolphthalein was colorless
Phenolphthalein was colorless, pH < 8.0
Bromocresol green was blue
Bromocresol green was blue, pH > 5.4
Methyl red was yellow
Methyl red was orange, pH > 6.2
Phenol red was yellow
Phenol red was yellow, pH < 6.4
a substance that changes color at a specific pH and is used to indicate the pH of the solution
INDICATOR
If you had an acid-base neutralization reaction that turned phenolphthalein pink and Thymolphthalein blue, what is the pH of the solution?
(a) 8.2
(b) 9.4
(c) 10
(d) Not enough information is available.
(d) Not enough information is available
. If you had an acid-base neutralization reaction that turned methyl violet blue and Thymol blue orange,
what is the pH of the solution?
a. 1.6
b. 2.0
c. 2.8
d. Not enough information is available.
b. 2.0