Introduction / Context:
Glass is a widely used material in windows, bottles, optical instruments and countless technological applications. General science questions often test basic knowledge of what ingredients go into common glass. While many substances can be added to modify properties, the core mixture used to make ordinary glass is based on silica-rich sand combined with other silicates and fluxes. Knowing this helps students connect chemistry with real-world materials.
Given Data / Assumptions:
• The question asks which mixture is used for making glass.
• Options list various combinations involving quartz, mica, salt, sand and silicates.
• We focus on ordinary soda-lime or silicate glass used in daily life.
Concept / Approach:
The main ingredient of most commercial glass is silica, which is obtained from sand (silicon dioxide). To form glass with appropriate melting temperature and properties, other silicates and compounds such as sodium carbonate and calcium oxide are added. These combine with silica to form a silicate network. Therefore, the correct combination must involve sand and silicate materials, rather than mixtures with common salt or minerals like mica alone.
Step-by-Step Solution:
1. Recall that ordinary glass is a silicate material, primarily made from silica obtained from sand.
2. Additional ingredients, such as soda and lime, act as fluxes and stabilizers, forming complex silicates.
3. Among the options, the one that clearly represents a silica and silicate mixture is ‘‘Sand and silicates’’.
4. ‘‘Quartz’’ is a crystalline form of silica, but quartz and mica alone are not the standard basic mixture for ordinary glass.
5. Salt (sodium chloride) is not the main raw material for glass manufacture; it may be present in trace amounts but is not a principal glass-making mixture.
6. Hence, the correct combination is ‘‘Sand and silicates’’.
Verification / Alternative check:
Industrial descriptions of glass manufacturing mention silica sand, soda ash and limestone as the major raw materials. When heated to high temperature, these substances react to form a molten silicate melt, which on cooling becomes glass. This confirms that sand (silica) and other silicates are central to the process. No standard glass-making process lists ‘‘salt and quartz’’ or ‘‘sand and salt’’ as the main mixture for ordinary glass.
Why Other Options Are Wrong:
Option A, ‘‘Quartz and mica’’, mentions minerals that may contain silica but does not represent the standard industrial mixture. Option B, ‘‘Salt and quartz’’, incorrectly highlights common salt, which is not a principal glass-making raw material. Option C, ‘‘Sand and salt’’, again overemphasizes salt and underrepresents the necessary silicate additives. All three distractors ignore the role of silicate fluxes and stabilizers that combine with sand in real glass manufacture.
Common Pitfalls:
A common mistake is to focus only on the presence of silica and assume that any silica-containing mineral is acceptable without considering industrial practice. Another pitfall is confusing the use of sodium compounds like soda ash (sodium carbonate) with common table salt (sodium chloride). Remember that ordinary glass is best remembered as being made from
sand and silicates, capturing both the silica source and the complementary silicate-forming ingredients.
Final Answer:
The basic mixture used for making ordinary glass consists mainly of
sand and silicates.
Discussion & Comments