Question

The silicon compound used in calico printing is:
A.Quartz
B.Silicon carbide
C.Sodium silicate
D.Silica

Answer 1

Hint: The term ‘calico’ is used to refer to a plain-woven textile which is made from unbleached and often not fully processed cotton. Calico printing is the process of printing and making fast – color designs on calico fabric. The silicon compound used in calico printing contains the silicate anion.

Complete step by step answer:
Quartz is the name of a chemical compound that consists of one part silicon and two parts oxygen. It is a hard and crystalline mineral. The silicon and oxygen atoms are linked in a continuous framework of silicon – oxygen tetrahedra. Each oxygen atom is shared between two tetrahedra giving an overall chemical formula of ${\text{Si}}{{\text{O}}_{\text{2}}}$ .
Quartz is a very useful natural material. It is very hard which makes it very durable which makes it an excellent abrasive material. Its luster and colour makes it very useful as a gemstone and also in glass making. Because of its resistance to both heat and chemicals, it is used as foundry sand. But it is not used in calico printing. So, A is not the correct option.
Silicon carbide having the formula ${\text{SiC}}$ is a semiconductor containing silicon and carbon. Because of its durability, it is often used as an abrasive material. It is also used in crucibles in foundry applications. But it is not used in calico printing. So, B is not the correct option.
Sodium silicate is the general name for chemical compounds having the formula ${\text{N}}{{\text{a}}_{{\text{2x}}}}{\text{S}}{{\text{i}}_{\text{y}}}{{\text{O}}_{{\text{2y + x}}}}$ such as sodium metasilicate, sodium orthosilicate etc. One of its main uses is as a fixative for hand dyeing with reactive dyes which require a high pH value to react with the textile fiber. It is applied on the dyed fabric and left to react for almost an hour at room temperature. Thus, it is used as a fixative in calico printing and so option C is correct.
Silica is an oxide of silicon having the formula ${\text{Si}}{{\text{O}}_{\text{2}}}$ . It most commonly occurs in nature as quartz. Thus, option D is also not correct.

Hence, option C is correct.

Note:
Another major application of sodium silicate solution is cement for producing cardboard.
It is also used as an iron flocculant and as an alum coagulant in wastewater treatment plants.
Sodium silicate gel is also used in aquaculture as an algal growth substrate.