Conductivity Lab
Materials:
Conductivity probe
DI water
Tap water
Anhydrous ethyl alcohol
Sucrose crystals
Sodium chloride crystals
1M HCl
0.1M HCl
Sodium hydroxide pellets
Glacial acetic acid
Concentrated Ammonia
Safety:
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Ware Goggles
Use special care when handling HCl, Glacial acetic acid, and Concentrated
Ammonia
Sodium hydroxide pellets should be transferred with a spatula. Do not allow them
to fall on the floor or remain on your desk surface. Immediately close the vial after
removing a pellet
Procedures:
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Clean and dry your testing plates. Note the numbers and identify each cavity
Fill the cavities according directions in the data table
Using conductivity probe, test the conductivity of the solution in cavity #1
Before testing the next solution, rinse the probe, blot excess water from probe with
a tissue and continue with the other cavities
Record the conductivity in the data table
Do not contaminate the solutions!!!
Data Table
Cavity
Substance
1
2
3
½ full tap water
10 drops ethyl alcohol
a. sodium chloride crystal
b. add 10 drops DI water
Sodium chloride crystal + 10 drops ethyl alcohol
a. sucrose crystal
b. add 10 drops DI water
Sucrose crystal+10 drops ethyl alcohol
10 drops 0.1M HCl
10 drops 1M HCl
a. sodium hydroxide pellet
b. allow pellet to stand for 10 minute, retest
c. add 10 drops DI water
a. 5 drops conc. ammonia
b. add 5 drops DI water
c. add 5 more drops DI water
d. add 5 more drops DI water
a. add 5 drops glacial acetic acid
b. add 5 drops DI water
c. add 5 more drops DI water
d. add 5 more drops DI water
10 drops conc. ammonia+ 10 drops glacial acetic acid
½ full DI water
4
5
6
7
8
9
10
11
12
13
Conductivity
value
Conductivity
Strength
(+, -, +/-)
Observations and Conclusions:
1. Did you observe a difference in conductivity between DI and tap Water? Explain
your observations
2. What type of electrolyte is tap water?
3. Compare the conductivity of sodium chloride crystals, sodium chloride in water,
and sodium chloride in ethyl alcohol. Which is a strong electrolyte? Why does
water behave differently from ethyl alcohol as a solvent for sodium chloride?
4. Compare the conductivity of the sucrose crystal, sucrose in water and in ethyl
alcohol. Explain the reason for the different observations
5. compare the conductivity of sodium chloride solution with the conductivity of
sucrose solution
6. What kind of electrolyte in 1M HCl? What kind of electrolyte in 0.1M HCl?
7. A sodium hydroxide pellet should not conduct electricity. Describe the change in
appearance of the sodium hydroxide pellet as it was exposed to the room
atmosphere
8. Explain why the conductivity of the sodium hydroxide pellet increased after 10
minutes. What happed to the conductivity of sodium hydroxide pellet as you added
water?
9. Is ammonia a strong or weak base? What happened to the conductivity of ammonia
as you added increasing amount of water?
10. What happened to the conductivity of acetic acid as you added increasing amount
of water? Is acetic acid classified as strong or weak acid?
This project is funded by a grant awarded under the President’s Community Based Job Training Grant as
implemented by the U.S. Department of Labor’s Employment and Training Administration (CB-15-162-06-60).
NCC is an equal opportunity employer and does not discriminate on the following basis:

against any individual in the United States, on the basis of race, color, religion, sex, national origin,
age disability, political affiliation or belief; and

against any beneficiary of programs financially assisted under Title I of the Workforce Investment Act
of 1998 (WIA), on the basis of the beneficiary’s citizenship/status as a lawfully admitted immigrant
authorized to work in the United States, or his or her participation in any WIA Title I-financially
assisted program or activity.
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