Question

Which of the following is not true for oxidation ?

• A. addition of oxygen
• B. addition of electronegative element
• C. removal of hydrogen
• D. removal of electronegative element

Answer 1

The Correct Option is D

To solve this problem, we need to understand the concept of oxidation in chemical reactions.

1. Definition of Oxidation:
Oxidation is generally defined as the process in which an element or compound loses electrons. It can also be described in terms of changes in bonding or the addition of certain elements to a molecule. Some common features of oxidation include:

• Addition of oxygen to a molecule.
• Loss of hydrogen from a molecule.
• Addition of electronegative elements to a molecule.

2. Analyzing the Options:
Let’s evaluate each option based on the definition of oxidation:

• Option (A) "Addition of oxygen" is a classic example of oxidation. When oxygen is added to a molecule, it increases the oxidation state of the atom, which is a characteristic of oxidation.
• Option (B) "Addition of electronegative element" is also consistent with oxidation. Adding an electronegative element, such as chlorine or oxygen, can cause an increase in oxidation state by pulling electrons away from other elements.
• Option (C) "Removal of hydrogen" is true for oxidation. The removal of hydrogen atoms (dehydrogenation) leads to an increase in the oxidation state, which is a typical example of oxidation.
• Option (D) "Removal of electronegative element" is incorrect. The removal of an electronegative element would decrease the oxidation state, which is a reduction process, not oxidation.

Final Answer:
The correct answer is (D) "Removal of electronegative element" because this is not true for oxidation.

Answer 2

Oxidation is typically defined by the following changes in a compound:

• Addition of oxygen: Oxidation often involves adding oxygen to a molecule (e.g., converting alcohols to aldehydes or ketones).
• Addition of electronegative element: Electronegativity is linked to oxidation because elements such as halogens (like chlorine) are often added in oxidation reactions, making the molecule more oxidized.
• Removal of hydrogen: Oxidation also involves the removal of hydrogen atoms from a molecule (e.g., oxidation of alkanes to alkene involves loss of hydrogen).

However, removal of electronegative element does not define oxidation. Removal of electronegative elements (like chlorine or oxygen) would lead to a reduction process, not oxidation.

The correct answer is (D) : removal of electronegative element.