Synthesis of Silicon Dioxide

Wash 100 g of yellow sand with water and dry the sand. Mix and react the sand with 52 g of sodium hydroxide, start to heat until the sodium hydroxide is molten for 20 minutes in a metal crucible, stir the mixture few times. Cool down the mixture and add water until all the soluble material dissolves, filter and collect the solution. Add hydrochloric acid until it doesn’t react anymore with the liquid, silicic acid is produced. To purify the jelly-like silicic acid, for every spoonful of silicic acid jelly add 500 mL of water, filter and collect the silicic acid. Heat the silicic acid in a crucible at 200°C, the silicic acid will decompose into silicon dioxide. Wash the silicon dioxide several times with water to get it very pure.

SiO2(sand) + 2NaOH = Na2O3Si + H2O

Na2O3Si + 2 HCl = 2 NaCl + H2O3Si

H2O3Si = SiO2 + H2O


Sand has reacted with the sodium hydroxide

Heated mixture was added to water and it was filtered

Adding hydrochloric acid

Silicic acid jelly

A spoonful of silicic acid jelly

Purifying the silicic acid

Purified silicic acid

Heating the silicic acid

The pure product

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