Question

\(\mathrm{CH}_{3} \mathrm{Cl}+\mathrm{Si} \mathrm{Cu} \frac{\mathrm{Cu} \text { Powder }}{570 \mathrm{~K}} \longrightarrow(\mathrm{X}) \stackrel{2 \mathrm{H}_{2} \mathrm{O}}{\longrightarrow}(\mathrm{Y})\) (Y) \& (X) respectively are, (a) \(\mathrm{SiCl}_{4}, \mathrm{Si}(\mathrm{OH})_{4}\) (b) \(\mathrm{Si}(\mathrm{OH})_{4}, \mathrm{SiCl}_{4}\) (c) \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{Si}(\mathrm{OH})_{2},\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiCl}_{2}\) (d) \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiCl}_{2},\left(\mathrm{CH}_{3}\right)_{2} \mathrm{Si}(\mathrm{OH})_{2}\)

Short answer

(d): \((\mathrm{CH}_3)_2\mathrm{SiCl}_2, (\mathrm{CH}_3)_2\mathrm{Si}(\mathrm{OH})_2\).

Step-by-step solution

Analyze the First Reaction

The reaction given is \( \mathrm{CH}_{3}\mathrm{Cl} + \mathrm{Si} \xrightarrow{\text{Cu Powder at } 570\,\mathrm{K}} (X) \). This reaction involves the synthesis of organosilicon compounds, where methyl groups \((\mathrm{CH}_3)\) are introduced onto the silicon atom. The only option that fits this reaction type is \((\mathrm{CH}_3)_2\mathrm{SiCl}_2\), meaning \((X) = (\mathrm{CH}_3)_2\mathrm{SiCl}_2\).

Analyze the Second Reaction

Next, we have \((X) \xrightarrow{2\mathrm{H}_2\mathrm{O}} (Y)\). Here \((X) = (\mathrm{CH}_3)_2\mathrm{SiCl}_2\), which reacts with water. The water will hydrolyze the \(\mathrm{Cl}\) atoms to \(\mathrm{OH}\) groups, forming \((\mathrm{CH}_3)_2\mathrm{Si}(\mathrm{OH})_2\) as \((Y)\). This type of reaction is typical for converting chlorosilanes to silanols.

Match Product Identities to Given Options

Option \((d)\) provides the correct identity for \((X)\) and \((Y)\) respectively: \((X) = (\mathrm{CH}_3)_2\mathrm{SiCl}_2\) and \((Y) = (\mathrm{CH}_3)_2\mathrm{Si}(\mathrm{OH})_2\). Confirm that these match the results from the previous steps. Therefore, the correct answer choice is \((d)\).

Key concepts

Organosilicon Compounds

Organosilicon compounds are a fascinating class of chemicals where silicon atoms are bonded to carbon-containing groups. These compounds play a vital role in both industrial and synthetic chemistry due to their unique properties and versatility.

• They often serve as precursors to silicones, which are used in a variety of products ranging from lubricants to adhesives.
• Their thermal stability and resistance to oxidation make them useful in high-temperature applications.
• In the realm of organic synthesis, organosilicon compounds can be used to shield certain groups within molecules, making them indispensable in complex reaction sequences.

A key component in creating these compounds involves a process called "silylation," where silicon atoms are introduced into organic molecules. Their ability to form stable bonds with a variety of elements broadens their utility in chemical reactions.

Chlorosilanes

Chlorosilanes are an important subgroup of organosilicon compounds. In these compounds, silicon is bonded to chlorine atoms. They serve as vital intermediates in the production of silicone polymers due to their reactive nature.
These compounds act as building blocks for several silicon-based materials and have a formula of the type \( ext{R}_n ext{SiCl}_{4-n} \), where \( ext{R} \) represents an organic group like a methyl (\( ext{CH}_3 \)) or ethyl group.

• These substances can undergo hydrolysis to form silanols, which further polymerize to form silicones.
• Chlorosilanes are generally manufactured through direct synthesis by reacting methyl chloride (\( ext{CH}_3 ext{Cl} \)) with silicon in the presence of a copper catalyst.

The resulting chlorosilane, like dimethyl dichlorosilane (\(( ext{CH}_3)_2 ext{SiCl}_2\)), can be further reacted to achieve the desired polymeric structure.

Hydrolysis Reaction

Hydrolysis is a chemical reaction that involves the breakdown of a compound by water. In organic chemistry, this reaction often converts halo compounds, such as chlorosilanes, into hydroxyl-containing compounds.
The reaction mechanism involves water molecules attacking the silicon-metal bond in the chlorosilane, replacing chlorine atoms with hydroxyl (\( ext{OH} \)) groups.

• This transforms chlorosilanes like \( ( ext{CH}_3)_2 ext{SiCl}_2 \) into silanols, represented as \( ( ext{CH}_3)_2 ext{Si}( ext{OH})_2 \).
• The hydrolysis process is a key step in forming stable silicon-oxygen bonds, crucial for silicone materials.

In the chemical industry, hydrolysis is utilized to create polymers and other products with specific physical properties, often facilitated by controlling temperature and reaction conditions.

Chemical Reaction Steps

Understanding the steps in a chemical reaction helps demystify the processes involved in transforming reagents into products. This sequential breakdown guides chemists in predicting reaction outcomes and optimizing processes.
The transformation of chlorosilanes to silanols illustrated by \( ext{CH}_3 ext{Cl} + ext{Si} \rightarrow ( ext{CH}_3)_2 ext{SiCl}_2 \rightarrow ( ext{CH}_3)_2 ext{Si}( ext{OH})_2 \) spans two primary reactions:

• Initially, the methyl chloride reacts with silicon in the presence of copper powder at high temperatures to form dimethyl dichlorosilane (\( X \)).
• Subsequently, this compound reacts with water in a hydrolysis step, converting (\( X \)) into dimethylsilandiol (\( Y \)).

Each reaction step involves specific conditions that must be managed carefully to ensure successful synthesis and avoid reaction by-products. These steps are crucial for understanding how simple substances can transform into more complex and useful compounds.