Question

What does glass rod made up of:
A) Metal silicates
B) Lime
C) Silicon dioxide
D) All of these

Answer 1

Hint: Glass rod also known as stirring rod, is commonly used in laboratories. It is crystalline solid made up of solid glass, which is a mixture of silica compounds. Refer to the raw materials used for the manufacturing of solid glass.

Complete step by step answer:
When crystalline quartz or silica is heated at a temperature of about 600^oC and melts to a colourless liquid and if this liquid is cooled rapidly then clear colourless transparent glassy mass is obtained called supercooled liquid which is an ordinary glass. Basically, glass is a supercooled liquid consisting of a mixture of silicates or it can be defined as a mixture of silicates of alkene or alkaline earth metal with some other constituents. The raw materials which are generally used for the manufacturing of glass are:
- Soda ash
- Lime
- Silica or silicon dioxide
- Borax
- Zinc oxide
- Lead oxide
- Potash Feldspar
Therefore on concluding, you can find that composition of glass rod includes metal silicates, lime, and silicon dioxide.
So, the correct answer is “Option D”.

Note: Usually, source of lime for glass manufacturing is limestone and source of silicon dioxide is quartz or white sand. Glass rods are quite hard and are used for mixing the chemicals. Glass rod has all the physical properties same as solid glass. It is transparent and a completely vitrified product. Glass rods are a good insulator of heat and electricity. Also, glass rods have low coefficient of cubical expansion which means there will be less change in volume upon heating.