Question

4) Pyrex or borosil glass is used for making laboratory apparatus , whereas crown glass is used in manufacture of optical instruments. Give a reason for the same.

Answer 1

• Pyrex has high ability to expand and thus resists heat rapidly. It is chemically resistant and can be used at high temperature also, and therefore is used in laboratory instruments.
• Crown glass has high density therefore it is used in manufacture of optical instruments. It is manufactured from alkali lime silicates having 10% potassium oxide. It has generally low refractive index.