Question

Hydrolysis of \(\mathrm{SiCl}_{4}\) gives (a) \(\mathrm{Si}(\mathrm{OH})_{4}\) (b) \(\mathrm{SiOCl}_{2}\) (c) \(\mathrm{SiO}_{2}\) (d) \(\mathrm{H}_{2} \mathrm{SiO}_{4}\)

Short answer

\(\mathrm{SiCl}_{4}\) undergoes hydrolysis to form \(\mathrm{Si}(\textrm{OH})_{4}\), which is option (a) silicon hydroxide.

Step-by-step solution

Understand the process of hydrolysis

Hydrolysis is a chemical reaction in which a compound reacts with water, often resulting in the decomposition of that compound and the formation of new substances.

Determine the products of hydrolysis for \(\mathrm{SiCl}_{4}\)

When \(\mathrm{SiCl}_{4}\) undergoes hydrolysis, it reacts with water. Each chlorine (Cl) atom is replaced by a hydroxyl (OH) group because water (H2O) supplies the hydroxyl groups and hydrogen ions. The complete replacement of all four chlorine atoms will result in the formation of \(\mathrm{Si}(\textrm{OH})_{4}\).

Confirm the correct answer

Based on the hydrolysis reaction, the correct product is \(\mathrm{Si}(\textrm{OH})_{4}\), which is silicon hydroxide. This is the compound formed when \(\mathrm{SiCl}_{4}\) is completely hydrolyzed by water.

Key concepts

Chemical Reactions

Chemical reactions are processes in which substances, known as reactants, transform into new substances called products. These transformations occur as a result of the breaking and forming of chemical bonds. In the context of hydrolysis reactions, specifically the hydrolysis of silicon tetrachloride (SiCl_4), water acts as a reactant to break bonds between silicon and chlorine atoms. This particular reaction is a type of substitution where hydroxyl groups from water replace chlorine atoms. All chemical reactions, including hydrolysis, must follow the law of conservation of mass, meaning the number of atoms of each element must remain equal before and after the reaction. For students, visualizing this conservation through balanced chemical equations reinforces understanding and assists in predicting products.

Hydrolysis Process

Hydrolysis is a fundamental chemical process where a water molecule (H_2O) is used to break down a compound. In hydrolysis reactions involving silicon compounds such as tetra-

chlorosilane (SiCl_4), water donates its hydroxyl groups (OH^−) to replace other atoms or groups in the compound. As a result, new compounds are formed along with the liberation of hydrogen ions (H^+) or other small molecules like hydrogen chloride (HCl). This reaction is crucial in both natural processes and industrial applications, including the production of silicon-based materials. Students should note that the hydrolysis process is profoundly affected by conditions such as temperature, concentration, and the nature of the reactants.

Silicon Compounds

Silicon compounds are a diverse group of materials composed of silicon, which is a metalloid, meaning it possesses properties intermediate between metals and non-metals. Compounds like silicon tetrachloride (SiCl_4) are used extensively in the semiconductor industry and for producing silicone polymers. Upon hydrolysis, SiCl_4 forms silicon hydroxide, Si(OH)_4, which can further condense to form silicon dioxide (SiO_2) and water. This types of transformations are vital for understanding the synthesis and manipulation of silicon-based materials. Students studying these compounds should pay particular attention to the valence shell electron pair repulsion (VSEPR) theory, which can help predict the shapes and reactivity of silicon-containing molecules.