Question

SI-SIO2-NA2SIO3-H2SIO3-SIO2-SI

Answer 1

1. Si + O2 -> SiO2

2. SiO2 + Na2O -> Na2SiO3

3. Na2SiO3 + 2HCl -> 2NaCL + H2SiO3

4. H2SiO3  -> SiO2 + H2O

5. SiO2 + 2Mg -> 2MgO + Si

Answer 2

SI-SIO2-NA2SIO3-H2SIO3-SIO2-SI

The given sequence of compounds is: Si, SiO2, Na2SiO3, H2SiO3, SiO2, Si.

Silicon (Si): Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, and lead are below it. It is relatively unreactive. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was able to prepare it in pure form. Its melting and boiling points of 1414 °C and 3265 °C respectively are the second-highest among all the metalloids and nonmetals, being only surpassed by boron. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is most widely distributed in dusts, sands, planetoids, and planets as various forms of silicon dioxide (silica) or silicates. Over 90% of the Earth's crust is composed of silicate minerals, making silicon the second most abundant element in the Earth's crust after oxygen. Silicon Dioxide (SiO2): Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula SiO2. It is most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and most abundant families of materials, existing both as several minerals and being produced synthetically. Notable examples include fused quartz, fumed silica, silica gel, and aerogels. It is used in structural materials, microelectronics (as an electrical insulator), and as components in the food and pharmaceutical industries. Sodium Silicate (Na2SiO3): Sodium silicate is a generic name for chemical compounds with the formula Na2xSiO2+x or (Na2O)x·SiO2, such as sodium metasilicate Na2SiO3, sodium orthosilicate Na4SiO4, and sodium pyrosilicate Na6Si2O7. The anions are often polymeric. These compounds are generally colorless transparent solids or white powders, and soluble in water in various amounts. Sodium silicate is also the technical and common name for a mixture of such compounds, chiefly the metasilicate, also called waterglass, water glass, or liquid glass. The product has a wide variety of uses, including the formulation of cements, passive fire protection, textile and lumber processing, manufacture of refractory ceramics, as adhesives, and in the production of silica gel. Orthosilicic Acid (H2SiO3): Orthosilicic acid is a chemical compound with the formula H4SiO4 or Si(OH)4. It is a weak acid. It only exists in dilute aqueous solutions. The acid itself has not been isolated and is only known in the form of its salts, such as sodium orthosilicate. Orthosilicic acid is formed by the hydrolysis of silicon compounds such as silicon tetrachloride or tetraethyl orthosilicate. It is used in the production of silica gel, ceramics, and as a nutritional supplement. To summarize the given sequence: - Si is the chemical symbol for silicon. - SiO2 is silicon dioxide, also known as silica. - Na2SiO3 is sodium silicate, a compound containing sodium and silicon. - H2SiO3 is orthosilicic acid, a weak acid containing silicon. - SiO2 is silicon dioxide, also known as silica. - Si is the chemical symbol for silicon.

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