Sodium silicate - (Na2O)xSiO2

What is Sodium silicate?

Sodium silicate is an inorganic sodium salt which has silicate as the counterion. It is also called Sodium metasilicate or Waterglass. The chemical formula of Sodium silicate is (Na2O)x·SiO2.

Sodium metasilicate is a flaked solid or powdered substance. It dissolves in water to produce alkaline solutions. It has a polymeric anion. In alkaline and neutral solutions it is stable whereas, in acidic solutions, the silicate ions will react with hydrogen ions and form silicic acids, which are likely to decompose into hydrated silicon on the dioxide gel. When further heated, it drives off the water and a hard translucent substance called silica gel is obtained.

Table of Contents

Properties of Sodium silicate – (Na2O)x·SiO2

Sodium silicate (Na2O)x·SiO2
Molecular weight of Sodium silicate 122.062 g/mol
Number of hydrogen bond acceptor 3
Complexity 18.8
Number of covalent bonds 3

Structure of Sodium silicate ((Na2O)x·SiO2)

Structure of Sodium silicate

Uses of Sodium silicate ((Na2O)x·SiO2)

  • Sodium silicate is used in wastewater treatment plants as an iron flocculant and an alum coagulant.
  • It is used as hand-dyeing as a fixative.
  • It is used in Pottery.
  • It is widely used in food preservation, homebrewing, and aquaculture.

Production of Sodium silicate

Sodium silicate solution can be prepared in a reactor by treating a mixture of silica, water, and caustic soda with hot steam. The reaction is as follows:

2x NaOH + SiO2 → (Na2O)x·SiO2 + x H2O

Sodium metasilicate can also be produced by dissolving silica SiO2 in molten sodium carbonate (Na2CO3) at a temperature of 851 °C

x Na2CO3 + SiO2 → (Na2O)x·SiO2 + CO2

Health hazards

It is a powerful irritant to eyes, mucous membrane, and skin. When this inorganic salt is ingested it can be toxic. Inhaling this compound causes sore throat, coughing, burning sensation, and shortness of breath.

Frequently Asked Questions – FAQs


What are the uses of sodium silicate?

Sodium silicates are used primarily in detergents, paper, water treatment, and construction materials. One of the greatest uses of sodium silicate solutions is as a cement for the manufacture of cardboard. If used as a paper glue, there is a tendency for the sodium silicate joint to break gradually after a few years, at which point the paper surfaces are no longer holding together.

How can sodium silicate be prepared?

Sodium silicate solutions can be created by treating a mixture of silica (generally in the form of quartz sand), caustic soda, and water in a reactor, with hot steam. Sodium silicates can also be obtained in molten sodium carbonate by dissolving SiO2 in it (whose melting point corresponds to 1713 ° C).

Why is sodium silicate employed in the treatment of concrete?

In most masonry products, concrete treated with a solution of sodium silicate helps to minimise porosity such as concrete, stucco, and plasters. This effect helps minimise water penetration, but has no known effect on minimising the absorption and emission of water vapour.

Learn more about the physical and chemical properties of Sodium silicate ((Na2O)x·SiO2) from the experts at BYJU’S.ts at BYJU’S.



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