Sodium carbonate is added to the tea mixture, in part, to form the sodium salt of...
Sodium carbonate is added to the tea mixture, in part, to form the sodium salt of the gallic acid present in tea. This salt is much more soluble than caffeine in water, and it is much less soluble than caffeine in dichloromethane.
(1) Suggest why the sodium salt of gallic acid should be highly soluble in water.
(2) What would happen to the gallic acid in the tea if no sodium carbonate solution were added during the procedure described in this experiment?
Homework Answers
Solution:
1) Sodium salt of gallic acid is more soluble in water because sodium salt of gallic acid is a ionic compound, hence it can form the ion-dipole interaction with water. Therefore, solubility enhanced in water.
2) The addition of sodium carbonate increases the solubilty of galic acid by formation of sodium salt of gallic acid. The formed salt becomes more soluble in water by interacting with water through strong ion-dipole interaction, therefore the extraction and yield of gallic acid will be greatly enhanced.
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Sodium carbonate is added to the tea mixture, in part, to form
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#1-6 1. Outline a separation scheme for isolating caffeine from tea. Use a flowchart similar in format to that shown...
#1-6
1. Outline a separation scheme for isolating caffeine from tea. Use a flowchart similar in format to that shown in Technique 2, Section 2.2. 2. Why was the sodium carbonate added in Experiment 13A? 3. The crude caffeine isolated from tea often has a green tinge. Why? 4. What are some possible explanations for why the melting point of your isolated caffeine was lower than the literature value (236°C)? 5. An alternative procedure for removing the tannins and gallic...
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#1-6
1. Outline a separation scheme for isolating caffeine from tea. Use a flowchart similar in format to that shown in Technique 2, Section 2.2. 2. Why was the sodium carbonate added in Experiment 13A? 3. The crude caffeine isolated from tea often has a green tinge. Why? 4. What are some possible explanations for why the melting point of your isolated caffeine was lower than the literature value (236°C)? 5. An alternative procedure for removing the tannins and gallic...
1. Outline a separation scheme for isolating pure caffeine from tea. Use a flowchart that begins with the tea bag and ends with the pure caffeine. Explain what is being separated at each step throughout the procedure. 2. Why was the sodium carbonate added to the tea solution? 3. The crude caffeine isolated from tea often has a green tinge. Why? 4. What are some possible explanations for why the melting point of your isolated caffeine was lower than the...
Classroom Activity 2: The Carbonate System When a carbonate salt, such as sodium carbonate, is placed into an acidic solution, carbonic acid (H.CO. weak acid, is formed. 1. Write the chemical formula for the carbonate ion. 2. Draw the Lewis structure for the carbonate ion. 3. How many hydrogen ions can react with the carbonate ion? 4. The chemical formula for carbonic acid is H.CO, How many K values does this acid have? 5. Starting from carbonic acid, write the...
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