Question

Anu wants to boil water quickly in a test tube. On observing the different zones of the flame, she is not able to decide which zone of the flame will be best for boiling water quickly. Help her in this activity.

Answer 1

Anu should boil the water in the hottest zone of the flame, which is a non luminous zone or the outermost zone of the flame. Non-Luminous zone would be best for boiling water quickly as the uppermost zone produces maximum heat.

Complete step by step answer:
There are three basic flame types: neutral (balanced), excess acetylene (carburizing), and excess oxygen (oxidizing). This will be the best part for Anu to quickly heat the test tube.
There are three different zones of a flame. In the outer zone of a flame, complete combustion of the fuel takes place because there is plenty of air around it, so water in a test tube will boil quickly in this zone. Due to complete combustion, the outer zone is blue. This zone is the hottest in temperature when compared to the other zones. This blue coloured zone is the non-luminous part of the flame. The yellow colour region which is the bright part of the flame is the middle zone. Middle zone is the zone which is moderately hot with limited supply of oxygen. The inner zone of the flame is black.
Thus, we know that Any should keep her test tube in the outermost zone which is the hottest part of the flame and has more temperature.

Therefore, the correct answer is the outermost zone.

Note: It is unaware to many that there are different zones in a flame. The outermost part of the flame is the non-luminous part of the flame and is generally blue in colour which is mainly due to the complete combustion.