Penyetaraan Reaksi Redoks Metode Perubahan Bilangan Oksidasi | Kimia Kelas 12

Summary

In this tutorial, the process of balancing redox reactions using oxidation numbers is thoroughly explained. The video covers the steps of identifying central atoms, calculating oxidation state changes, and equalizing these changes through strategic use of coefficients. It also demonstrates how to balance the reaction in both acidic and basic conditions by adding H⁺, OH⁻, and H₂O. Detailed examples, including reactions in acidic and basic environments, help clarify each step, making it easier for viewers to understand and apply these concepts in their own redox reaction problems.

Takeaways

• 😀 Understanding redox reactions involves balancing oxidation states and ensuring atom and charge conservation.
• 😀 The first step in balancing redox reactions using oxidation numbers is identifying the atoms that undergo changes in oxidation state.
• 😀 Oxidation states are determined for each atom involved in the reaction, and the difference in oxidation numbers helps to balance the equation.
• 😀 In acidic solutions, H+ ions are added to balance the charge, while in basic solutions, OH- ions are added to maintain charge balance.
• 😀 The number of atoms of the central atom (the atom whose oxidation state changes) must be equal on both sides of the equation.
• 😀 After balancing oxidation states, the next step is to balance the charges by adding H+ or OH- ions, depending on the solution type.
• 😀 Once oxidation states and charges are balanced, oxygen atoms are balanced by adding H2O molecules to the side lacking oxygen.
• 😀 The final step is ensuring that hydrogen atoms are also balanced by adjusting the coefficients of H2O molecules accordingly.
• 😀 A key part of balancing redox reactions is multiplying the coefficients by factors that equalize the changes in oxidation numbers between the atoms.
• 😀 Two examples in the script demonstrate the step-by-step process for balancing redox reactions in acidic and basic conditions, showcasing how to apply these principles to complex reactions.

Q & A

What is the method used to balance redox reactions in the video?

The video explains balancing redox reactions using oxidation numbers. This method involves several steps: identifying atoms whose oxidation states change, calculating the change in oxidation numbers, balancing the changes, and then balancing the number of atoms and charges using H⁺ or OH⁻ ions (depending on acidic or basic conditions).

What is the first step in balancing a redox reaction using oxidation numbers?

The first step is to identify the central atoms in the reaction. These are the atoms whose oxidation states change during the reaction.

How do you calculate the change in oxidation numbers?

The change in oxidation numbers is calculated by comparing the oxidation state of an atom before and after the reaction. The difference between these values shows the extent of oxidation or reduction.

What do you do after calculating the change in oxidation numbers?

After calculating the change in oxidation numbers, the next step is to balance these changes. This is done by ensuring that the total increase in oxidation states equals the total decrease, which is achieved by adjusting the coefficients in the reaction.

How do you balance the charges in the reaction?

To balance charges, if the reaction occurs in an acidic solution, H⁺ ions are added to the side with the smaller charge. In a basic solution, OH⁻ ions are added to the side with the larger charge.

In acidic conditions, how do you balance the number of hydrogen and oxygen atoms?

In acidic conditions, the number of hydrogen and oxygen atoms is balanced by adding H₂O molecules to the side with fewer oxygen atoms and H⁺ ions to balance the hydrogen atoms.

What is the difference between balancing redox reactions in acidic and basic conditions?

In acidic conditions, H⁺ ions are added to balance the charge and hydrogen atoms, while in basic conditions, OH⁻ ions are used for balancing charge and hydrogen atoms. Afterward, if necessary, H₂O is used to balance oxygen atoms.

What role does H₂O play in balancing redox reactions?

H₂O is used to balance the number of oxygen atoms in the reaction. If one side of the equation has fewer oxygen atoms, H₂O molecules are added to that side.

Can you explain the process of balancing a reaction in acidic conditions with an example?

Yes, for example, in the reaction between Cr₂O₇²⁻ and C₂O₄²⁻, the first step is to balance the atoms by adjusting the coefficients. Afterward, H⁺ ions are added to balance the charges on both sides. Finally, H₂O is used to balance oxygen and hydrogen atoms.

How do you determine which atom undergoes oxidation and which undergoes reduction?

Oxidation involves an increase in the oxidation number, and reduction involves a decrease. For example, in the reaction with Cr₂O₇²⁻, Cr undergoes reduction (its oxidation state decreases from +6 to +3), while C in C₂O₄²⁻ undergoes oxidation (its oxidation state increases from +3 to +4).