Question

Water glass is made up of:
A. Glass made up of water
B. Sodium silicate
C. Water gas
D. Crystal carbonate

Answer 1

Hint: Water glass is the commonly used name for an aqueous solution of either alkali metal silicate. It is also sometimes called the “liquid glass”. So it is made up of the silicate of an alkali metal.

Complete Solution :
Water glass, commonly called sodium silicate, is a mixture of compounds having chemical formula \[{{\text{(N}{{\text{a}}_{2}}\text{O)}}_{m}}\cdot{{\text{(Si}{{\text{O}}_{2}})}_{n}}\]. Its main constituent is sodium metasilicate (\[\text{N}{{\text{a}}_{2}}\text{O.Si}{{\text{O}}_{3}}\]).

- Water glass is a crystalline solid that is soluble in water, forming alkaline solutions. It is manufactured and sold as solid lumps or powders or as a clear, syrupy liquid. It is used as a convenient way to generate sodium or as a source of sodium for many industrial products, as a builder in laundry detergents, as a binder and adhesive, as a flocculant in water-treatment plants, and in many other applications.
One of the reactions involved in the formation of water glass is mentioned below:

\[\text{mN}{{\text{a}}_{\text{2}}}\text{C}{{\text{O}}_{\text{3}}}\text{ }\!\!~\!\!\text{ + Si}{{\text{O}}_{\text{2}}}\to \text{ (N}{{\text{a}}_{\text{2}}}\text{O}{{\text{)}}_{m}}\text{.Si}{{\text{O}}_{\text{2}}}\text{ }\!\!~\!\!\text{ + C}{{\text{O}}_{\text{2}}}\]
So, the correct answer is “Option B”.

Note: The following are the steps to prepare water glass or sodium silicate in laboratory:
1. Wear proper safety gear, which includes gloves and eye cover.
2. Heat 4 to 8 grams of sodium hydroxide in 10 mL of water.
3. Once the sodium hydroxide is hot and dissolved, slowly add 6 grams of crushed silica gel beads carefully. Heat the solution between the successive additions.
4. The sodium silicate or water glass is formed as a product of this reaction.
It is generally extremely hazardous in case of skin contact (corrosive, irritant), of eye contact (irritant), of ingestion, of inhalation.