Sel Elektrokimia (3) | Deret Volta | Kimia kelas 12

Summary

In this video, the concept of the Volta series in electrochemistry is explored, where metals are ranked by their electrode potentials. The series helps explain oxidation and reduction behaviors, with metals on the left more easily oxidized and those on the right more easily reduced. Practical examples demonstrate how different metals react with water, acids, and other metals, showing their ability to displace ions based on their position in the series. The video concludes with problem-solving examples to reinforce the understanding of electrode potential in chemical reactions.

Takeaways

• 😀 Volta’s series is a list of metals arranged by their electrochemical potential, indicating how easily they can be reduced or oxidized.
• 😀 Metals with higher electrode potential are more likely to undergo reduction (gain electrons) and act as strong oxidizing agents.
• 😀 Metals with lower electrode potential are more likely to undergo oxidation (lose electrons) and act as strong reducing agents.
• 😀 A useful mnemonic to remember the order of metals in Volta’s series is the Indonesian 'jembatan keledai' phrase.
• 😀 Hydrogen (H2) has a potential of zero and serves as a reference in Volta's series; metals to the right of H2 are more likely to gain electrons, while metals to the left are more likely to lose them.
• 😀 Metals such as lithium (Li) can react with water to release hydrogen gas, while others react with acids.
• 😀 Metals to the left of hydrogen can react with dilute acids to release hydrogen gas (e.g., Zn reacts with H2SO4 to release H2).
• 😀 Volta’s series can be used to predict displacement reactions, where one metal can replace another from its solution.
• 😀 The order of displacement reactions follows the principle that a metal can displace another from its solution if its potential is lower.
• 😀 Understanding the relative positions of metals in Volta's series helps in predicting reactions like metal displacements and hydrogen gas production in different environments.
• 😀 Practice problems help reinforce the understanding of Volta’s series, such as arranging metals by their electrode potentials based on their ability to displace hydrogen or other metals.

Q & A

What is the electrochemical series (deret volta)?

The electrochemical series (deret volta) is a list of metals arranged in order of their electrode potentials. Metals with higher electrode potentials are more easily reduced, while metals with lower electrode potentials are more easily oxidized.

How do we determine the reactivity of metals using the electrochemical series?

The reactivity of metals is determined by their position in the electrochemical series. Metals that are positioned on the left (with lower electrode potentials) are more likely to undergo oxidation, while metals on the right (with higher electrode potentials) are more likely to undergo reduction.

What does it mean if a metal is more easily reduced?

If a metal is more easily reduced, it has a higher electrode potential, meaning it has a stronger tendency to gain electrons and undergo reduction reactions.

What role does hydrogen (H2) play in the electrochemical series?

Hydrogen (H2) acts as the reference point in the electrochemical series, with an electrode potential of zero. Metals with electrode potentials greater than zero will tend to reduce (gain electrons), while metals with lower potentials will tend to oxidize (lose electrons).

How does the electrochemical series relate to oxidation and reduction reactions?

In the electrochemical series, metals with lower electrode potentials (on the left) tend to be oxidized, while metals with higher electrode potentials (on the right) tend to be reduced. The series helps predict which metal will oxidize or reduce in a given reaction.

What is a mnemonic used to remember the electrochemical series?

A mnemonic example provided in the video is 'lihat ke bawah Candi nampak Mang Ali minum air,' which serves as a memory aid to recall the order of the metals in the electrochemical series.

Which metals react with water to produce hydrogen gas?

Metals from Li to Mn in the electrochemical series can react with water to produce hydrogen gas (H2).

How do metals react with dilute acids according to the electrochemical series?

Metals from Li to Pb react with dilute acids, such as H2SO4, to release hydrogen gas, as these metals have lower electrode potentials and are more likely to undergo oxidation.

How can the electrochemical series predict displacement reactions?

The electrochemical series can predict displacement reactions by comparing the electrode potentials of metals. A metal with a lower electrode potential can displace a metal with a higher potential from its salt solution, reducing it in the process.

What happens in the displacement reaction example involving Na and Al?

In the example, sodium (Na) can displace aluminum (Al) from its compound, forming NaOH and reducing Al. This happens because Na has a lower electrode potential than Al, meaning Na is more easily oxidized and Al is more easily reduced.