Hidrolisis Garam dari Asam Lemah dan Basa Kuat | Materi Hidrolisis Garam | Kimia SMA | Pojan.id

Summary

This educational video script discusses the hydrolysis of a third type of salt, which is produced from the reaction between a weak acid and a strong base. It explains why this salt, exemplified by CH3COONa, exhibits basic properties with a pH greater than 7. The script delves into the ionization process, the role of cations and anions in hydrolysis, and how the hydrolysis of the anion from a weak acid results in the formation of OH- ions, thus increasing the pH. It also provides a formula to calculate the concentration of OH- ions and subsequently the pH of such salts, using the example of CH3COONa and another salt, CaCN2, to illustrate the calculation process.

Takeaways

• 🧪 The video discusses the hydrolysis of a third type of salt, specifically those resulting from the reaction between a weak acid and a strong base.
• 🔍 It explains that the third type of salt, such as CH3COONa, is basic in nature and has a pH greater than 7 due to the hydrolysis reaction involving the anion from the weak acid.
• 📚 The script covers the concept that salts can be categorized into four types based on their hydrolysis properties.
• 🌡 The video aims to answer why the third type of salt exhibits basic properties and why its pH is above 7.
• ⚗️ It demonstrates through the example of CH3COONa, which is formed from the reaction between acetic acid (CH3COOH), a weak acid, and sodium hydroxide (NaOH), a strong base.
• 🔬 The process of ionization of the salt into cations and anions is explained, with the cation (Na+) originating from the strong base and the anion (CH3COO-) from the weak acid.
• 🌟 The video emphasizes that only the anion from a weak acid can undergo hydrolysis, while the cation from a strong base cannot.
• 💧 The hydrolysis reaction involves the anion reacting with water to form the original weak acid and hydroxide ions (OH-), which increases the pH above 7.
• 📉 The script provides a formula to calculate the concentration of hydroxide ions produced during hydrolysis, which is essential for determining the pH of the salt solution.
• 📝 The video script guides through the process of determining the pH of the salt solution by first finding the concentration of hydroxide ions and then using it to calculate the pH value.
• 🔑 The final part of the script promises to cover the last type of salt, resulting from the reaction between a weak acid and a weak base, in the next video, including its hydrolysis reaction and pH calculation method.

Q & A

What is the main topic discussed in the script?

The main topic discussed in the script is the hydrolysis of salts, specifically the third type of salt which is produced from the reaction between a weak acid and a strong base.

What are the characteristics of the third type of salt mentioned in the script?

The third type of salt is characterized by being the product of the reaction between a weak acid and a strong base, and it is basic in nature with a pH value greater than 7.

Why is the third type of salt basic and have a pH greater than 7?

The third type of salt is basic and has a pH greater than 7 because the anion from the weak acid can undergo hydrolysis, reacting with water to produce hydroxide ions (OH-), which increases the pH.

What is the example of the third type of salt discussed in the script?

The example of the third type of salt discussed in the script is sodium acetate (CH3COONa), which is formed from the reaction between acetic acid (CH3COOH) and sodium hydroxide (NaOH).

How does the hydrolysis reaction of the anion from the third type of salt occur?

The hydrolysis reaction of the anion from the third type of salt occurs when the anion reacts with water, accepting a proton (H+) from water to form the original weak acid and releasing hydroxide ions (OH-).

What is the relationship between the pH and pOH of a solution, and how is it used to find the pH of the third type of salt?

The relationship between the pH and pOH of a solution is that pH + pOH = 14. To find the pH of the third type of salt, one can first determine the pOH using the concentration of hydroxide ions produced by hydrolysis and then use the relationship to find the pH.

How is the concentration of hydroxide ions produced by the hydrolysis of the third type of salt calculated?

The concentration of hydroxide ions produced by the hydrolysis of the third type of salt is calculated using the formula: [OH-] = √(Kw / Ka), where Kw is the ion product of water, Ka is the acid dissociation constant of the weak acid, and the concentration of the anion from the salt.

What is the role of the acid dissociation constant (Ka) in calculating the pH of the third type of salt?

The acid dissociation constant (Ka) represents the equilibrium constant for the ionization of the weak acid. It is used in the formula to calculate the concentration of hydroxide ions produced by hydrolysis, which is then used to determine the pH of the salt solution.

How does the script explain the concept of complete ionization of the salt?

The script explains the concept of complete ionization by assuming that the salt fully dissociates into its constituent ions. This assumption is used to calculate the concentration of the anion from the known concentration of the salt.

What is the conclusion about the pH of the third type of salt based on the hydrolysis reaction?

The conclusion is that the pH of the third type of salt is greater than 7 because the hydrolysis reaction of the anion results in the production of hydroxide ions, making the solution basic.