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Oxidation

Oxidation is a change in which a substance gains oxygen, loses hydrogen, or loses electrons.

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Student-friendly explanation

In Class 10 chemistry, oxidation is easy to spot when oxygen is added or hydrogen is removed. In electron language, oxidation also means loss of electrons. Many common examples, such as burning magnesium or forming metal oxides, show oxidation clearly.

How to write this in exams

  1. 1

    Start with the exact idea

    Oxidation is a change in which a substance gains oxygen, loses hydrogen, or loses electrons.

  2. 2

    Then show how to use it

    1. Check whether oxygen is added or hydrogen is removed. 2. If electron transfer is given, see whether electrons are lost. 3. Name the substance as oxidized.

  3. 3

    Add one concrete example

    When magnesium burns in air to form magnesium oxide, magnesium gets oxidized.

  4. 4

    Avoid this incomplete answer

    Saying the substance is reduced because it forms a compound. That is wrong because oxidation is decided by oxygen, hydrogen, or electron change, not by compound formation alone.

Definition

Oxidation is a change in which a substance gains oxygen, loses hydrogen, or loses electrons.

Example

When magnesium burns in air to form magnesium oxide, magnesium gets oxidized.

Rule to remember

Oxidation = addition of oxygen, removal of hydrogen, or loss of electrons.

Memory hook

Oxidation: add oxygen, lose hydrogen, lose electrons.

Examples and method

Worked example

Mg + O2 → MgO. Magnesium gains oxygen, so magnesium is oxidized.

Method to apply

1. Check whether oxygen is added or hydrogen is removed. 2. If electron transfer is given, see whether electrons are lost. 3. Name the substance as oxidized.

Diagram support

Show a simple reactant to product arrow and mark oxygen addition or electron loss above the arrow.

How CBSE asks it

Students may be asked to identify oxidation in a reaction, or to state whether oxygen is added or electrons are lost.

Avoid common mistakes

Common confusion

Students often think oxidation means only adding oxygen, but electron loss is also an important sign of oxidation.

Common wrong answer

Saying the substance is reduced because it forms a compound. That is wrong because oxidation is decided by oxygen, hydrogen, or electron change, not by compound formation alone.

Exam tip

In an exam answer, mention both the oxygen-based idea and the electron-based idea when possible.

Quick check

A substance combines with oxygen during a reaction. What type of change is this?

This is oxidation because adding oxygen to a substance is one of the standard signs of oxidation.

Study the oxidation diagram carefully

Use the labelled diagram to keep oxidation clear in short answers and revision.

What this diagram makes clear

This diagram keeps the labels and direction of oxidation in the right order.

Where this helps in exams

Use this for labelled diagram work and short exam answers on oxidation.

Revision cue

Revise oxidation through the labels before writing the answer.

Answer writing and exam use

1-mark answer

Oxidation is a change in which a substance gains oxygen, loses hydrogen, or loses electrons.

2-mark answer

Oxidation is a change in which a substance gains oxygen, loses hydrogen, or loses electrons. Oxidation = addition of oxygen, removal of hydrogen, or loss of electrons. When magnesium burns in air to form magnesium oxide, magnesium gets oxidized.

3-mark answer

In Class 10 chemistry, oxidation is easy to spot when oxygen is added or hydrogen is removed. In electron language, oxidation also means loss of electrons. Many common examples, such as burning magnesium or forming metal oxides, show oxidation clearly. Oxidation = addition of oxygen, removal of hydrogen, or loss of electrons. Mg + O2 → MgO. Magnesium gains oxygen, so magnesium is oxidized. Students may be asked to identify oxidation in a reaction, or to state whether oxygen is added or electrons are lost. Saying the substance is reduced because it forms a compound. That is wrong because oxidation is decided by oxygen, hydrogen, or electron change, not by compound formation alone.
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