1 | P a g e

Jordan University of Science and Technology

Faculty of Engineering

Civil Engineering Department

CE 453

“Environmental lab”

“Acid-Base Titration Curves and Acid-Base

Indicators”

Experiment (3)

Student Name: Anas Mohammad Maghayreh.

Student ID: 20120023117.

Section #:1

Submission Date: 15/7/2015.

Submitted to: Dr. Hani Abu Qdais

2 | P a g e

Abstract:* Titration is an analytical method used to determine the exact amount of a

substance by reacting that substance with a known amount of another

substance. The completed reaction of a titration is usually indicated by a

color change or an electrical measurement. An acid/base neutralization

reaction will yield salt and water. In an acid-base titration, the neutralization

reaction between the acid and base can be measured with either a color

indicator or a pH meter. Acid + Base Salt + Water

:Introduction*

The study of acid-base titrations involves consideration of the reactions,

which occur between acids and bases. For this purpose, it is convenient to

distinguish between strong and weak acids and bases.

The term strong usually refers to a substance, which is completely

dissociated into its ions in solution while weak, generally refer to substance,

which is partially dissociated .of course, various degree of strong and weak

exist.

The reaction of strong base and strong acid involves the combination of H+

and OH- to form H2O and it is governed by the Ion product of water. The

titration of weak acid with a strong base involves at least two sequential

reactions, the initial reaction is the titration of the hydrated proton with OH

added .the second reaction, which may very rapid or slow, involves transfer

of the proton from the weak acid to H2O .in some cases, additional reactions

may be involved, the pH of the equivalence point.

Acid-base indicators which are usually an organic acids that contain an

ionizable proton H+ , these indicators change in color under specific H+

activity. To know the equivalence point an indicator that change color at that

point can be used.

In this experiment, a phenolphthalein color indicator will be used and methyl

orange. Phenolphthalein is colorless in acidic solutions and pink in basic

solutions.

3 | P a g e

:Objective*

1. To determine the inter action of acids and bases and to examine methods for

determining equivalence points of reactions.

2. determining equivalence points in acids-bases titration using a PH meter or acid

- base indicators

:Apparatus*

1- PH meter.

2- Calomel reference electrode.

3- Bursts.

4- Magnetic stirrer

Picture (1): PH meter.

Picture (2): Magnetic stirrer

Picture (3): flask with buret

4 | P a g e

*Sample:

*Procedure:

1- Develop the titration curves to determine the equivalence points for

titration of :

a- 50 ml of 0.1M H2SO4 & 0.1M of NaOH .

b- 50 ml of 0.1M acetic acid & 0.1M NaOH .

2- Add 3 drops of an appropriate indicator to the 50ml of 0.1M H2SO4 and

insert the PH electrode and observe the PH values. Then titrate the

solution with 0.1M NaOH until the indicator change in color.

3- Repeat part 2 for another appropriate indicator.

4- Repeat part 2 and 3 for titration of 0.1M acetic acid with 0.1M NaOH

using an appropriate indicators.

:Results and Calculations*

Table1.1: volume of Phenolphthalein & methyl orange with change if PH

H2SO4 with Phenolphthalein H2SO4 with methyl orange

NaOH PH NaOH PH 0.0 2.42 0 2.4

0.5 2.42 0.5 2.44

1.0 2.42 1 2.5

1.5 2.45 1.5 2.56

2.0 2.55 2 2.65

2.5 2.70 2.5 2.87

3.0 3.10 3 3.2

3.5 4.70 3.5 6.5

4.0 10.5 - -

5 | P a g e

*Discussion: in this experiment we know that any volume of strong acid need the same volume

of strong base to get the equilibrium point where at which the pH must be 7 where

the moles of each of them are becomes equal and so the concentration of H+ and

OH- but that wasn't in our experiment .

The acid base titration is very important especially for environmental engineering

when treating the waste water and the need to clear it to become more useful.

our readings of PH was almost accurate but

There were some errors in this experiment and the data is not accurate

because of the following reasons:-

Some personal errors like reading errors caused by the eye or the

non-horizontal taken reading.

Some Factorial errors in the PH measure.

The dishes were not clean from the first

The taken reading was not taken at the accurate time .

*Conclusion: when we added methyl orange to H2SO4 the color was converted from

orange to yellow and when we added phenolphthalein to H2SO4 the solution

was converted from colorless to the pink color

From this experimental it can concluded that any volume of strong acid need

the same volume of strong base to get the equilibrium point which the pH

must be 7 where the moles of each of them are becomes equal and so the

concentration of H+ and OH- but that wasn't in our experiment .

CH3COOH volume(ml)

PH CH3COOH volume(ml)

PH

0 3.3 0 3.3

0.5 3.55 0.5 3.6

1 3.8 1 4

1.5 4.3 1.5 4.2

- - 2 4.45

- - 2.5 4.7

- - 3 5

- - 3.5 5.4

- - 4 6

- - 4.5 10

Table1.2: volume of Phenolphthalein and PH

6 | P a g e

Once again this process is very important specially for civil engineering

when treating with waste water and the need to clear it to become more

useful so it is very important to know everything of the kinetic of the reaction

of components with water and how to change the PH to make the reaction

going on and what is should do.

*References: Lab manual

lab notes

Wikipedia (chemistry)

*Appendix:

0

2

4

6

8

10

12

0 2 4 6

H2SO4 with Phenolphthalein

Series1

0

1

2

3

4

5

6

7

0 1 2 3 4

H2SO4 with methyl Orange

Series1

0

1

2

3

4

5

0 0.5 1 1.5 2

CH3COOH with methly orange

Series1

0

2

4

6

8

10

12

0 2 4 6

CH3COOH with Phenolphthalein

Series1