Question

Crystalline form of Sulphur is:
A. Plastic sulphur.
B. Colloidal sulphur.
C. Monoclinic sulphur.
D. All of these.

Answer 1

Hint: There are two forms of sulphur namely crystalline and amorphous form of sulphur and each type has different types of allotropes. So, to find out the correct option look into each option. Hint here is Monoclinic sulphur is a type of crystalline sulphur which remains stable at temperature above $369K.$

Complete step by step answer:
Allotropes are referred to as the property of having and existing in different structural forms in the same physical state. They are different as the one or more different physical forms of an element. There are two types of sulphur namely crystalline (that comprises of monoclinic and rhombic sulphur) and the other one is the amorphous (which comprises of three allotropes namely plastic sulphur, colloidal sulphur and milk of sulphur).
Plastic sulphur is a type of amorphous sulphur and is generally not stable at all temperatures. Colloidal sulphur is also a type of amorphous sulphur, that is prepared by mixing the solution of alcohol and sulphur in water.
Two holes are made in the crust and remaining liquid is poured out. On removing the crust, colourless needle shape crystals of monoclinic sulphur are formed. Therefore, we see that out of each option monoclinic sulphur is the crystalline form of sulphur.

So, the correct answer is Option C.

Note: The rhombic sulphur is also known as octahedral sulphur. This sulphur is yellow in colour and is considered as the most stable sulphur among other forms of sulphur. It is insoluble in water and is prepared by evaporating the solution of rolled sulphur in carbon disulphide.