Hi matchette!!
If the pH of the solution is 9, this means that we have a basic
solution (not an acidic solution).
Litmus Paper:
It is a paper with a powder extracted from certain plants. It is used
to test the pH of a solution. An acidic solution turns it red; a basic
solution turns it blue; neutral solutions don´t change paper color.
The intensity of the color red or blue depends on the pH. More pH over
7 more intense is the blue, and less pH under 7 more intense is the
red.
In that case the solution has pH 9, then the litmus paper will turn into blue.
For more references read the following document (see the page 3):
"A very common acid-base indicator is called litmus. An acid will
react with litmus to produce a red color, while the reaction of a base
with litmus produces a blue color. Some compounds are neither acidic
nor basic and are referred to as neutral compounds. These compounds
will not change the color of
neutral litmus paper. Thus, a simple and safe test for determining the
acidity or basicity of a solid compound is to dissolve it in water and
test the resulting solution with litmus paper."
From "What Is It? Identifying an Unknown Compound" at Chemistry
Department of Boston College website.
http://chemserv.bc.edu/ugrad/lab/gen/IDunknown.pdf
---------------------------------------------------------
Phenolphthalein:
Phenolphthalein's color change from pink (base) to colorless (acid)
occurs near pH 8-10.
-Color chart-
·Colorless in an acid.
·A faint pink in a neutral solution.
·Bright pink in a base.
See a Phenolphthalein color chart at this page:
"Acid/Base Titration":
http://www.howe.k12.ok.us/~jimaskew/ctitrate.htm
In this case the solution pH is 9, then the phenolphtalein will turn
the solution color to a little hard pink.
---------------------------------------------------------
Methyl orange:
Methyl orange turns yellow in an alkaline solution and red in an acidic solution.
In this case (with a solution pH of 9), the methyl orange will turn
the solution color to yellow.
----------------------------------------------------------
For a more complete understanding about pH indicators with the color
charts, please visit the following page:
"ACID-BASE INDICATORS" from Chemguide:
http://www.chemguide.co.uk/physical/acidbaseeqia/indicators.html
----------------------------------------------------------
Search strategy:
ph indicators
phenolphtalein color
methyl orange color
litmus paper color
Search engine used:
www.google.com
I hope this helps you; if you find something unclear, please post a
request for an answer clarification before rate this answer.
Best regards.
livioflores-ga |
