Question

With the help of labelled diagram explain the following:

Regular fire extinguisher.

Answer 1

• A fire extinguisher contains Sodium bicarbonate powder. There is also dilute sulphuric acid placed in a glass capsule. 
• On pressing the knob, the capsule breaks and sulphuric acid comes in contact with the sodium bicarbonate. These two react chemically to release CO₂ which comes out.
• CO₂ based fire extinguishers do not cause corrosion and are non-conductors of electricity. Therefore, they are used when electrical or electronic equipment catches fire.
• CO₂ based fire extinguishers are used to extinguish small scale fire. It is beyond their capacity to extinguish a big fire.
• In modern fire extinguishers liquid and solid CO₂ is filled under pressure. On reducing the pressure, it becomes gaseous and comes out forcefully through the horn-like hose pipe.
• Chemical reaction:

Internal structure of fire extinguisher