Dow CST Award 2024 - ร.ร.เตรียมอุดมศึกษาเปร็งฯ "การผลิตและทดสอบคุณสมบัติของโซเดียมไฮดรอกไซด์(NaOH)"

Summary

The script details an experiment involving the production and testing of sodium hydroxide (NaOH) solutions. The procedure includes creating a low-concentration NaOH solution, testing its properties as a base, examining its electrical conductivity, and observing chemical reactions. The experiments explore sodium hydroxide's reactions with various substances, including phenolphthalein, sodium bicarbonate, and glucose. Additionally, a reaction with vegetable oil produces soap. This hands-on approach showcases sodium hydroxide's uses in industry and its impact on the environment, highlighting safe practices and the importance of precise experimental design.

Takeaways

• 😀 The experiment focuses on the production and testing of sodium hydroxide (NaOH) solutions, which are used in various industrial applications.
• 😀 Sodium hydroxide is a strong base, and its reactions need to be carefully controlled due to potential environmental hazards.
• 😀 In the experiment, a low-concentration sodium hydroxide solution is produced to ensure safety and minimize pollution risks.
• 😀 Sodium hydroxide solutions can conduct electricity, and this is tested by measuring the conductivity in different solutions.
• 😀 The experiment demonstrates the reactivity of sodium hydroxide, particularly in its ability to produce hydrogen gas at the cathode and oxygen gas at the anode.
• 😀 The experiment also shows the basic nature of sodium hydroxide by using a pH indicator, which changes from purple to green when mixed with the solution.
• 😀 Methylene blue is used to test for electron transfer and redox reactions, changing colors depending on the presence of electrons.
• 😀 Sodium hydroxide reacts with oils to produce soap through a saponification reaction, which demonstrates its ability to break down fats and oils.
• 😀 The solution of sodium hydroxide created during the experiment is safe to use in low concentrations, but excessive amounts can lead to pollution and other environmental issues.
• 😀 The experiments underscore the importance of handling sodium hydroxide with care, especially in terms of concentration and disposal, to prevent harm to the environment and public health.

Q & A

What is the primary purpose of the experiment described in the transcript?

The primary purpose is to design and test the properties of sodium hydroxide (NaOH) solution, focusing on its production, electrical conductivity, chemical reactions, and environmental impact.

Why is it important to use sodium hydroxide in low concentrations and small quantities?

Sodium hydroxide should be used in low concentrations and small quantities to minimize its harmful environmental effects and reduce pollution, ensuring safety while maintaining its effectiveness in experiments.

What is the significance of testing the electrical conductivity of sodium hydroxide solution?

Testing the electrical conductivity of sodium hydroxide solution helps to understand its ionic properties and its ability to conduct electricity, which is an important characteristic for its use in various industrial applications.

What happens at the cathode and anode during the electrolysis of sodium chloride in the experiment?

At the cathode (negative side), hydrogen gas is produced, while at the anode (positive side), oxygen gas is generated. This demonstrates the process of electrolysis of sodium chloride.

How does sodium hydroxide act as a base in the experiment?

Sodium hydroxide acts as a base by neutralizing acids, as demonstrated when it changes the color of a pH indicator from purple to green, which corresponds to a basic solution.

What was observed during the electrical conductivity test between sodium hydroxide and sodium bicarbonate solutions?

The sodium hydroxide solution caused the light bulb to shine brighter than the sodium bicarbonate solution, indicating that the sodium hydroxide solution has a higher electrical conductivity due to its strong ionization.

What reaction occurs when sodium hydroxide solution is mixed with methylene blue and glucose?

When sodium hydroxide solution is mixed with methylene blue and glucose, the methylene blue is reduced by glucose in a basic environment, changing from blue to colorless. Shaking the mixture causes the color to return to blue due to the release of oxygen gas.

What is the role of sodium hydroxide in the soap-making process described in the experiment?

Sodium hydroxide is used to saponify oils, reacting with fatty acids in plant oils to form sodium salts of fatty acids, which are the main components of soap.

Why is it necessary to observe the reactions and results of the sodium hydroxide solution during the experiment?

Observing the reactions allows researchers to verify the chemical properties of sodium hydroxide, its ability to conduct electricity, and its behavior in various reactions, ensuring accurate and reproducible results.

What safety precautions should be considered when handling sodium hydroxide in this experiment?

Sodium hydroxide is a caustic substance, so proper safety measures should include wearing gloves, goggles, and protective clothing. The experiment should also be conducted in a well-ventilated area to avoid exposure to harmful fumes.