Question

Bones glow in the dark because:
(a) they contain shining material
(b) they contain red phosphorus
(c) white phosphorus undergoes slow combustion in contact with air
(d) white phosphorous changes into red form

Answer 1

Hint: The bones shine or glow in the absence of light due to the presence of the non-metal which belongs to the 15th group and 3rd period of the periodic table and belongs to the nitrogen family and is a block element. This non-metal forms fumes in the air which shows a glowing effect. Now answer the statement.

Complete answer:
First of all, we will discuss the bones. Bones are a part of the human skeleton system and are generally made up of calcium and the phosphorus atom.
Calcium is an alkali metal and belongs to the s-block element and is an essential component in the bones and a major part of the bones are made up of the calcium atom.
On the other hand, phosphorus belongs to the nitrogen family and is a p-block element and is also an important element present in the bones. Because it is highly reactive, phosphorus in its elementary forms exists in the following two types i.e. the white phosphorus and the red phosphorus.
Out of these two forms of phosphorus, white phosphorus is less stable and highly reactive and on coming in contact with the oxygen present in the air , results in the formation of fumes which shows glowing effects in the dark.
So, the bones glow in the dark because white phosphorus undergoes slow combustion in contact with the air.

Hence, option (c) is correct.

Note: The phenomenon of emitting light or glowing of white phosphorus in the absence of the light or in the dark is known as the phosphorescence and white phosphorus will only show this effect in the presence of air i.e. the oxygen.