Oxidation is defined as

Options

A. addition of electropositive element
B. addition of electronegative element
C. removal hydrogen
D. addition of ionic molecule

Answer

### Step-by-Step Text Solution:

1. **Understanding Oxidation**:
- Oxidation is a chemical process that involves the transfer of electrons. It is often defined in terms of changes in the oxidation state of an element.

2. **Addition of Oxygen**:
- One common definition of oxidation is the addition of oxygen to a substance. When a substance reacts with oxygen, it often increases its oxidation state.

3. **Removal of Hydrogen**:
- Another aspect of oxidation is the removal of hydrogen from a substance. When hydrogen is removed, the oxidation state of the remaining elements can increase.

4. **Addition of Hydrogen**:
- In some contexts, oxidation can also be defined as the addition of hydrogen to a compound, especially in organic chemistry. However, this is less common and can lead to confusion.

5. **Overall Definition**:
- Therefore, oxidation can be summarized as the process involving the addition of oxygen, the removal of hydrogen, or an increase in oxidation state.

### Summary:
- Oxidation is defined as the addition of oxygen, removal of hydrogen, or an increase in oxidation state of an element in a chemical reaction.