How to: Perform an

Acid-Base Titration

Connie Bisesi

Before Experiment:

Fill out the know and want to know sections of

the following KWL chart regarding acid-base

titrations:

file:///Users/uconn922/Desktop/KWL%20Sheet

%20For%20Connie%20Bisesi.webarchive

What is an Acid-Base Titration?

An acid or base of known concentration

neutralizes an acid or base of the unknown

centration.

The experiment is monitored by visual

indicators and pH electrodes in order to find the

reaction’s equivalence point.

Purpose of the Experiment

In this acid-base titration, you will determine the

molarity of an unknown solution of NaOH

(base) by titrating in with a known solution of

HCL (acid). To do so, use the equation:

M1 x V1 = M2 x V2

Key Things to Note

In order to know when neutralization has

occurred, a sudden color change in the

indicator will be present. This means that the

moles of the acid is equal to the moles of the

base, called the endpoint.

Brief Overview of Experiment

https://www.youtube.com/watch?v=g8jdCWC10vQ

Step 1: Hypothesis

Form a hypothesis (an educated guess) about

the results of the experiment. You will be

testing the accuracy of your hypothesis.

Step 2: Gather Materials

● 50 mL Buret

● 10 mL Graduated

Cylinder

● Distilled Water

● Phenolphthalein

● Buret Clamp

● Safety Goggles

● 125 mL Erlenmeyer Flask

● 200 mL beaker

● .1 M NaOH

● HCl

● Stirring plate

Step 3: Clean Equipment

Rinse the buret, graduated

cylinder, and erlenmeyer

flask with distilled water.

Dry the equipment

thoroughly with paper

towels.

Step 4: Addition of NaOH

Set up the buret to sit nicely in the buret clamp,

with a 200 mL beaker beneath it. Add 50 mL of

base (NaOH) to the buret. Make sure to get rid

of air bubbles in the lower end by opening the

spout on the bottom. Record the volume to the

nearest .01 mL in the data table.

Data Table

Amount of Solution (in mL)

Initial volume of .10 M NaOH (in buret)

Initial volume of HCL (in beaker)

Final volume of .10M NaOH (in buret)

Step 5: Obtaining HCl

Obtain 10 mL of HCl by measuring it out in the

graduated cylinder, and transferring it to the

erlenmeyer flask.

Step 6: Addition of H2O

In the erlenmeyer flask, add 50 mL of distilled

water (measured with the graduated cylinder)

and two drops of phenolphthalein. Record the

volume in the data table.

Data Table

Amount of Solution (in mL)

Initial volume of .10 M NaOH (in buret)

Initial volume of HCL (in beaker)

Final volume of .10M NaOH (in buret)

Step 7: Magnetic Stirrer

Place the erlenmeyer flask on the stirring plate

under the tip of the buret (removing the beaker)

on a moderate speed, 5.

Step 8: Titration

Very slowly, add 1 mL from the buret into the

erlenmeyer flask until the solution in the flask

turns a faint pink for more than 30 seconds.

Note: If the color in the flask turns to a dark

pink, the solution was over titrated.

Step 9: Measuring End Point

Measure and record the volume of the buret at

the end point of the reaction in the data table.

Data Table

Amount of Solution (in mL)

Initial volume of .10 M NaOH (in buret)

Initial volume of HCL (in beaker)

Final volume of .10M NaOH (in buret)

Step 10: Cleaning of Equipment

Turn off the stirring plate and release the buret

from the buret clamp. Wash all the equipment

with distilled water, dry, and put away in its

correct place.

Step 11: Calculate Molarity

Plug in your data and solve for M2 ( the

concentration of HCl)

M1 x V1 = M2 x V2

M1: .10 M

V1: Final volume - initial volume of NaOH

V2: Initial volume of HCl

Step 12: Review Hypothesis

Review whether your results match your

hypothesis and either accept or reject it. Lastly,

finish the what I have learned in the following

KWL chart:

file:///Users/uconn922/Desktop/KWL%20Sheet

%20For%20Connie%20Bisesi.webarchive