medium importancemedium difficulty5 min

Bleaching Powder

Bleaching powder is a chlorine-based compound used for bleaching and for disinfecting water.

In one line: Bleaching powder: white cloths, safe water.

Practice This Concept

Understand it

Bleaching powder is an important household and municipal chemical.
It is used to bleach cotton, linen, and wood pulp, and it is also used to disinfect drinking water.
Its action is linked to chlorine release under suitable conditions.
It should be stored in a dry, tightly closed container because moisture reduces its strength.

Example

A water tank may be treated with bleaching powder to kill germs and make the water safer for use.

Rule to remember

Bleaching powder is commonly written as CaOCl₂.

It is prepared from chlorine and slaked lime in school-level chemistry discussion.

See it worked out

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

Worked example

1If a city water tank contains bleaching powder, the water becomes safer because harmful germs are reduced.
2This is why the compound is used in water treatment.

Method you can reuse

1First recall that bleaching powder is chlorine-based.
2Then connect it with two standard uses: bleaching materials and disinfecting water.
3Finally remember dry storage for better shelf life.

Visual tip

A simple tank diagram with a dose of bleaching powder going into water can show its disinfecting use.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

Why is bleaching powder added to a municipal water tank?

Think first, then show answer

It is added to disinfect the water and kill germs, which makes the water safer for use.

Common wrong answer

A common wrong answer is to call it a cleaning detergent.

Why it loses marks: Its main school-level use is bleaching and disinfection, not ordinary washing.

Don't mix this up

Students often think bleaching powder is the same as ordinary detergent or liquid bleach. It is a different chemical with specific uses.

Exam tip

For board answers, mention both uses: bleaching and disinfection. Also mention dry storage to keep it effective.

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

Questions usually ask about its uses, storage conditions, or why it is helpful in water treatment and bleaching.

1
Enough for 1 mark
Bleaching powder is a chlorine-based compound used for bleaching and for disinfecting water.
2
Add for 2 marks
Example: A water tank may be treated with bleaching powder to kill germs and make the water safer for use.
3
Add for 3 marks
Bleaching powder is an important household and municipal chemical.

MCQ Quiz

Practice this concept with focused MCQs

Open the concept quiz intro first, review the test details, and then start a focused MCQ set from this concept only. Instant score and answer review are live now.

10 MCQs5 MinutesInstant Results