Measurement of Ph Using Indicators

Running head: MEASUREMENT OF PH USING INDICATORS 1
Measurement of Ph Using Indicators
Name of Student
Institution Affiliation

MEASUREMENT OF PH USING INDICATORS 2
Introduction
Background
In their scholarly work, Chemistry Education Research and Practice, Cartrette & Mayo,
states that, “An acid-base indicator is a chemical species that changes color at a specific pH as
the pH (acidity) of the solution is varied.” However, Bronsted and Lowery describes the
interaction between acids and bases with regards to the transfer of protons between the chemical
species. It describes an acid as that which can give out a proton H+, while a base as that which
can accept a proton (Cartrette & Mayo, 2011). Further, the acid, structure-wise is that chemical
which must contain a hydrogen atom, whereby it will thus dissociate it in the form of an ion. The
on Bronsted and Lowery theory is significant as it helps in the description of acid-base reactions
in any solvent (Cooper et al., 2016). Some examples which justify the theory includes
Fig1: Bronsted and Lowery equations, (Brawner, 2015).
Besides, the weak acids and bases form the acid-base indicators. They have a ph ranges
either close to the neutral ph., for a weak acid, or further from the ph., for a weakly basic

MEASUREMENT OF PH USING INDICATORS 3
solution. They act as indicators since the color of both the acid form of the indicator is not
similar to the basic form of indicator (Cartrette & Mayo, 2011).
Objectives
 To understand how to use indicators to test the ph
 To understand the difference between acids and bases.
Experimental Section
By using deionized water, five small test tubes were rinsed and dry them. 1ml of 0.1 M
HCl was then added to each of the test tubes. All the tests tubes were labeled to be sure of the
indicator added. To each of the test tubes, one of the seven indicators in the table was then
added. By means of observation, a comparison of the colors in each test tube was made and
recorded down. This will help in determining the 0.1M HCl ph., within one ph. Unit (Orgován &
Noszál, 2011). The observed color as well as the possible ph. range of the indicator solution was
as well noted. The application of the remaining solutions then repeated the same procedure. For
instance, H2O CH3COONa, HCl, CH3COOH, Na2CO3, NH3, Al2(SO4)3, and Unknown
solution. The quantity was maintained at 0.1 M. Finally; the obtained results were recorded in a
clean datasheet (Laboratory-manual)
Results
Table 1. Solutions tested
TB BPB BCG BCP BTB PR AY pH
H2O Olive Purple Green Yucky
red
Light
olive
Orang
e
Yellow 7.0
CH3COON
a
Diarrhe
a color
Bright
purple
Blue Dark
purple
Dark
green
Bright
orange
Yellow 8.5
HCl Ruby
red
Yellow Orange Yellow Orange Orang
e
Orange 1.0
CH3COOH Bright
orange
Diarrhe
a color
Yellow
-orange
Yellow Orange Orang
e
Scramble
d egg
2.9