CHEM 219
Lab Report & Lab Notes
Exp#: 8 Synthesis of Azo dye
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, Chemistry Lab Report
Experiment #: 8
Title: Synthesis of Azo dye: methyl orange
Purpose:
The purpose of the experiment is to synthesize azo dye, methyl orange and to test its
properties as an acid-base indicating dye.
Procedure:
1. Add a 5% sodium carbonate solution to a 600 mL beaker with a magnetic stirrer.
2. Start the stirring gently and add 5.2g of sulfanilic acid and allow it to stir until it
dissolves. Use water rinse down the sides of the beaker.
3. Take 1.8g of sodium nitrate that has been dissolved in 10 mL of water and add it
to the sulfanilic acid solution.
4. Cool the solution in a slush of ice and water until the temperature is between 0
and 5 degrees.
5. Add a solution of 3mol of concentrated HCl dissolved in 5mL of water to acidify
the solution. Add it slowly and drop-wise over a period of time.
6. Take 3g of the reagent N,N-dimethylanaline and acidify it with 1.5 mL of glacial
acetic acid.
7. To perform the coupling reaction, combine the solutions to produce methyl
orange.
8. Remove the synthesized methyl orange from the ice bath. Add a solution of
sodium hydroxide made by dissolving 3.5g of sodium hydroxide and 10 mL of
water.
9. To help precipitate the solid methyl orange, add 10g of solid NaCl.
10. Filtrate the solution with suction filtration using the Buchner funnel. Wash well
with water to remove traces of acid or base and any ionic byproducts.
11. Wash with ice cold ethanol to help purify the solid methyl orange.
12. After filtration, remove the solid methyl orange from the funnel and allow it to dry.
13. Take a small quantity of the synthesized methyl orange and make a solution.
14. Basify the solution with 1 molar of sodium hydroxide and acidify it with 1 molar
HCl and observe the pH/color changes.
Data/Results/Calculations:
The synthesis was successful in producing the acid-base indicating azo dye, methyl
orange. We observed the acid-base indicating behavior using 1.0M HCl and 1.0M
NaOH to alter the pH of a dilute solution of the dye and noted the color changes.
-Orange: basic form
-Acidic form: red
-pH color change range – 3.2-4.4
This study
Chem219Experiment8docx/
Lab Report & Lab Notes
Exp#: 8 Synthesis of Azo dye
Portage Learning
Inside you will get:
- Clear, Concise Scientific Language.
- All Tables and Figures Labelled Clearly.
- Included Units for All Measurements.
- Proofread Report.
- Portage Learning.
, Chemistry Lab Report
Experiment #: 8
Title: Synthesis of Azo dye: methyl orange
Purpose:
The purpose of the experiment is to synthesize azo dye, methyl orange and to test its
properties as an acid-base indicating dye.
Procedure:
1. Add a 5% sodium carbonate solution to a 600 mL beaker with a magnetic stirrer.
2. Start the stirring gently and add 5.2g of sulfanilic acid and allow it to stir until it
dissolves. Use water rinse down the sides of the beaker.
3. Take 1.8g of sodium nitrate that has been dissolved in 10 mL of water and add it
to the sulfanilic acid solution.
4. Cool the solution in a slush of ice and water until the temperature is between 0
and 5 degrees.
5. Add a solution of 3mol of concentrated HCl dissolved in 5mL of water to acidify
the solution. Add it slowly and drop-wise over a period of time.
6. Take 3g of the reagent N,N-dimethylanaline and acidify it with 1.5 mL of glacial
acetic acid.
7. To perform the coupling reaction, combine the solutions to produce methyl
orange.
8. Remove the synthesized methyl orange from the ice bath. Add a solution of
sodium hydroxide made by dissolving 3.5g of sodium hydroxide and 10 mL of
water.
9. To help precipitate the solid methyl orange, add 10g of solid NaCl.
10. Filtrate the solution with suction filtration using the Buchner funnel. Wash well
with water to remove traces of acid or base and any ionic byproducts.
11. Wash with ice cold ethanol to help purify the solid methyl orange.
12. After filtration, remove the solid methyl orange from the funnel and allow it to dry.
13. Take a small quantity of the synthesized methyl orange and make a solution.
14. Basify the solution with 1 molar of sodium hydroxide and acidify it with 1 molar
HCl and observe the pH/color changes.
Data/Results/Calculations:
The synthesis was successful in producing the acid-base indicating azo dye, methyl
orange. We observed the acid-base indicating behavior using 1.0M HCl and 1.0M
NaOH to alter the pH of a dilute solution of the dye and noted the color changes.
-Orange: basic form
-Acidic form: red
-pH color change range – 3.2-4.4
This study
Chem219Experiment8docx/
