Question

While cooking, if the bottom of the vessel is getting blackened on the outside, it means that
A. The food is not cooked completely
B. The fuel is not burning completely
C. The fuel is wet
D. All of the above

Answer 1

Hint: Sooty flames are the yellow flames that contain unburnt particles in it which are black in color.

Complete step-by-step answer:
There are two types of flames
- Sooty flame
- Non Sooty flame

Sooty flame is yellow in color. In this type of flame there are various unburnt particles in it. That unburnt particles can be completely unburnt or partially unburnt. Those unburnt particles are known as soot and they are black in color. Therefore, vessels turn black those who are put over the sooty flame.
The unburnt particles are there due to lack of oxygen available for oxidation which might be due to blockage of air holes present in the burner. The particles that are released by this flame causes pollution and contributes to particulate matter of air which in turn damages the health of living organisms.

Non Sooty flame is blue in color and in this flame,fuel is burnt completely. It is the flame that burns clean fuel which does not leave impurity and cause pollution to the atmosphere.
If the fuel would be wet then it will produce smoke in the atmosphere and if the food is not cooked properly then may proper time is not taken to cook or there is insufficient fuel.
But if the vessel is turning black during cooking that means fuel is not burning completely.
The correct answer is B.

Note: Sooty flame also known as yellow flame contains unburnt particles due to inefficient burning of fuel that is due to incomplete oxidation of fuel which in return gets deposited on the vessel kept over it turns the vessel black. Therefore, while cooking; if the bottom of the vessel is turned out black that means fuel is not burnt completely.