Question

Acetylene reacts with acetic acid in presence of \(\mathrm{Hg}^{+}\) ions at room temperature to give: (a) Ethyl acetate (b) Acetaldehyde (c) Vinyl acetate (d) Methyl acetate

Short answer

The correct product formed is vinyl acetate (c).

Step-by-step solution

Identify the Reactants

The reactants in this chemical reaction are acetylene, which has the formula C_2H_2, and acetic acid, CH_3COOH.

Recognize the Converter

The presence of Hg^+ ions indicates this is a hydration reaction under the influence of the mercuric ion catalyst.

Predict the Reaction Outcome

Acetylene, with Hg^+ catalyst and acetic acid, reacts to produce vinyl acetate CH_2=CHOOCCH_3. Vinyl acetate formation is typical with these reactants and conditions, involving addition across the triple bond.

Verify Product Formation

Vinyl acetate is formed by the addition of the carboxylate part of acetic acid across the triple bond in acetylene, facilitated by Hg^+ ions.

Key concepts

Acetylene Chemistry

Acetylene, with its chemical formula \( ext{C}_2 ext{H}_2\), is a simple alkyne. Alkynes are characterized by having a carbon-carbon triple bond. This triple bond is a powerful feature in organic chemistry. Why? Because it is very reactive. The reactivity comes from the fact that there are two pi bonds that can break and form new bonds with other atoms or groups. Acetylene is a foundational molecule that is used in creating more complex organic compounds. The triple bond makes acetylene a popular choice in many chemical reactions because it can undergo addition reactions easily.
What are addition reactions? Simply put, it's when other atoms or groups are added across the multiple bonds of a molecule. In the context of acetylene, this means atoms from other reactants can add across its triple bond, turning it into a new compound. One of the exciting things about acetylene chemistry is that it allows the formation of a variety of products depending on the reactants and catalysts used.

Vinyl Acetate Formation

Vinyl acetate, with the chemical formula \( ext{CH}_2= ext{CHOOCCH}_3\), is a vital compound in the world of organic chemistry. It's primarily produced through the reaction of acetylene and acetic acid in the presence of mercury ions as a catalyst. This process is a clear demonstration of how chemical reactions can transform simple molecules into more complex ones.
How does this reaction occur? This is where acetylene's reactivity truly shines. The acetic acid (\( ext{CH}_3 ext{COOH}\)) contributes the carboxylate part that bonds across acetylene’s triple bond. The reaction typically results in the replacement of one hydrogen atom on the acetylene with the carboxylate group, forming vinyl acetate. Thus, acetylene and acetic acid, when used together with a mercury catalyst, create a pathway for converting simple raw materials into commercially valuable vinyl acetate.
Vinyl acetate is not just any compound. Its relevance extends to producing polyvinyl acetate (PVAc), which is an adhesive component in glues and paints. The formation of vinyl acetate by adding across the acetylene bond with appropriate catalysts like mercury ions illustrates organic chemistry's elegance and efficiency in synthesis.

Mercury Catalysts in Organic Reactions

Mercury catalysts, particularly mercury ions like \( ext{Hg}^+\), play a crucial role in many organic reactions. The presence of these catalysts can make or break a chemical process, depending on the nature of the reaction involved. Mercury catalysts are known to facilitate reactions that involve alkynes, particularly through hydration and other addition reactions.
Why use mercury ions? In the acetylene and acetic acid reaction, the \( ext{Hg}^+\) ions help stabilize the reaction intermediate. This stabilization is key, as it makes the addition of groups across the acetylene's triple bond much more feasible. It’s important to note that mercury catalysts act by influencing the chemical environment around the reactants, lowering the energy barrier needed for the reaction to proceed thus improving reaction efficiency.
Despite their usefulness, mercury catalysts are handled with care because of their environmental and health implications. Scientists actively work to find safer alternatives with similar catalytic properties. Nonetheless, the use of mercury in catalyzing reactions like the formation of vinyl acetate from acetylene underscores its role in advancing industrial chemistry.