Which statement best describes Borosilicate, Aluminosilicate, and High Silica glass in laboratory use?

• A. All have high thermal resistance due to silica content
• B. They are all leaded glass
• C. They are all opaque
• D. They conduct electricity

Answer: (A)

The key idea is that these glasses are valued in the lab for their ability to withstand heat and rapid temperature changes, thanks to their silica-rich networks. The silicon-oxygen framework forms a rigid, interconnected structure that lowers thermal expansion and raises the melting point, making the glass resistant to thermal shock. In borosilicate glass, adding boron oxide further stabilizes the structure and reduces expansion, boosting thermal resistance. Aluminosilicate glass adds aluminum oxide, which strengthens the network and enhances chemical durability. High silica glass has a very high silicon dioxide content, giving excellent thermal stability and resistance to heat and chemicals.

Because of this, they are not leaded glass, since lead oxide would alter chemical behavior and transparency. They are also not opaque; these are typically transparent, uniform glasses. And glass generally acts as an electrical insulator, not a conductor, so conductivity is not a characteristic advantage of these materials.