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Redox Reaction

A redox reaction is a reaction in which oxidation and reduction happen at the same time.

In one line: Redox means reduction plus oxidation.

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Understand it

Redox reactions are important because one substance loses electrons while another gains them. In many Class 10 examples, one reactant gains oxygen and another loses oxygen, or electrons move from one substance to another.

Example

Copper oxide with hydrogen is a redox reaction because copper oxide is reduced and hydrogen is oxidized.

Rule to remember

Redox = oxidation + reduction together in the same reaction.

See it worked out

Follow the example line by line, then use the same method on new questions.

Worked example

  1. 1CuO + H2 → Cu + H2O.
  2. 2CuO loses oxygen and hydrogen gains oxygen, so both processes happen together.

Method you can reuse

  1. 1Find the substance that loses oxygen or electrons.
  2. 2Find the substance that gains oxygen or electrons.
  3. 3If both are present, the reaction is redox.

Sketch it in your answer

Mark one reactant as oxidized and the other as reduced in the same reaction arrow.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

A reaction shows one substance losing oxygen while another gains oxygen at the same time. What type is this?

Think first, then show answer
It is a redox reaction because oxidation and reduction are happening together.

Common wrong answer

Calling it only oxidation because oxygen is present. That is incomplete, because the other substance is reduced at the same time.

Don't mix this up

Students may describe only oxidation or only reduction and forget that both occur together.

Exam tip

If one substance is oxidized, check which other substance is reduced in the same reaction.

Write it in the exam

Each point is worth about one mark. Write point 1 for a 1-mark question and keep adding points as the marks go up.

How CBSE asks it

You may be asked to identify the oxidized and reduced substances in one equation.
  1. 1

    Enough for 1 mark

    A redox reaction is a reaction in which oxidation and reduction happen at the same time.

  2. 2

    Add for 2 marks

    Example: Copper oxide with hydrogen is a redox reaction because copper oxide is reduced and hydrogen is oxidized.

  3. 3

    Add for 3 marks

    Redox reactions are important because one substance loses electrons while another gains them.

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