Problem 10 - Biology Concepts and Applications

Question

A molecule that donates electrons becomes ________, and the one that accepts the electrons becomes ______ . a. reduced; oxidized b. ionic; electrified c. oxidized; reduced d. electrified; ionic

Step-by-Step Solution

Answer

The molecule that donates electrons becomes oxidized, and the one that accepts electrons becomes reduced; thus, the answer is c.

Step 1: Understanding Oxidation and Reduction

In chemical reactions, oxidation refers to the loss of electrons by a molecule, atom, or ion, whereas reduction refers to the gain of electrons. This can be remembered by the mnemonic OIL RIG, which stands for 'Oxidation Is Loss, Reduction Is Gain' of electrons.

Step 2: Identifying Electron Donor and Acceptor

In a redox reaction (reduction-oxidation reaction), the molecule that donates electrons undergoes oxidation because it loses electrons. Conversely, the molecule that accepts electrons undergoes reduction as it gains electrons.

Step 3: Selecting the Correct Answer

Given that the molecule donating electrons is oxidized and the one accepting electrons is reduced, the correct choice corresponds to c, 'oxidized; reduced,' as per the rules of redox reactions.

Key Concepts

Understanding Oxidation

Oxidation is a vital concept in redox reactions, where it signifies the loss of electrons from an atom, ion, or molecule. Think of oxidation as practically the opposite of gaining. It can sometimes be confusing because oxidation is often associated with oxygen, but it is all about electron loss.

• "Oxidation is loss of electrons," is the basic rule to remember and use.
• We can see examples in everyday life, such as metal rusting.

When a molecule loses electrons, it increases in oxidation state, often leading to changes in its properties. This transformation can influence reactions that involve metals or non-metals. Each time atoms in a reaction become capable of losing electrons, they undergo oxidation.

Essentials of Reduction

Reduction is the counterpart to oxidation in redox reactions. While oxidation involves losing electrons, reduction is all about gaining electrons. This principle completes the cycle of give-and-take in chemical interactions.

• "Reduction is gain of electrons," helps remember this concept easily.
• Think of reduction as making something "fuller," by adding electrons.

Reduction decreases the oxidation state of a substance, often rendering it more stable or reactive, depending on the context. This process is not just theoretical; it's the backbone of many biological and industrial processes, like breathing where oxygen is reduced in the body.

Role of the Electron Donor

In any redox reaction, the electron donor plays a pivotal role. This is the entity that willingly parts with its electrons, undergoing oxidation in the process. The electron donor:

• Transfers electrons to another molecule, which usually gets reduced.
• Acts like a bridge enabling other molecules to reach a more reduced state.

Understanding electron donors is crucial in systems from rechargeable batteries to photosynthesis, where they drive the transfer of energy. These processes reflect how electron donors support the cycle of energy conversion and storage in natural and man-made environments.