Question

Ether is obtained by the reaction of ethyl alcohol and \(\mathrm{H}_{2} \mathrm{SO}_{4}\) at (a) \(474 \mathrm{~K}\) (b) \(383 \mathrm{~K}\) (c) \(413 \mathrm{~K}\) (d) \(273 \mathrm{~K}\)

Short answer

Ether is produced at 413 K from ethanol and sulfuric acid.

Step-by-step solution

Identify the Chemical Reaction

The chemical reaction used to produce ether from ethyl alcohol (ethanol) involves dehydration. The reaction is known as dehydration of alcohol, where ethanol (C_2H_5OH) is converted to ether (C_2H_5OC_2H_5) with the help of sulfuric acid (H_2SO_4).

Determine the Optimal Temperature

The production of ether from ethanol under the influence of H_2SO_4 typically occurs at a specific temperature. For optimal ether formation, the reaction is often conducted at a moderate temperature, allowing etherification rather than forming alkene. This temperature is known to be around 413 K.

Select the Correct Temperature

Given the temperature options (a) 474 K, (b) 383 K, (c) 413 K, and (d) 273 K, we must choose the temperature closest to the optimal condition for ether production. From the options, 413 K is the correct temperature.

Key concepts

Dehydration of Alcohols

Dehydration of alcohols is a chemical process used to remove a molecule of water from an alcohol. Specifically, in the context of ether formation, dehydration typically involves a primary alcohol like ethanol. During this reaction, two molecules of ethanol combine by losing a water molecule to form an ether. In general, the reaction can be represented as: \[2 ext{{C}}_2 ext{{H}}_5 ext{{OH}} ightarrow ext{{C}}_2 ext{{H}}_5 ext{{OC}}_2 ext{{H}}_5 + ext{{H}}_2 ext{{O}}\] This type of reaction requires the presence of a strong acid, commonly sulfuric acid, to act as a catalyst. Understanding this process is crucial, as the dehydration reaction involves a balance where temperature plays a key role, helping to steer the reaction towards the formation of either an ether or an alkene.

Ethanol

Ethanol, also known as ethyl alcohol, is a volatile, flammable, and colorless liquid. It's one of the simplest forms of alcohol, having the molecular formula \( ext{C}_2 ext{H}_5 ext{OH}\). In the laboratory setting and industrial processes, ethanol serves as an essential reactant due to its capability to engage in various chemical reactions. In ether formation, ethanol acts as both a reactant and a source of the hydrocarbon chains in the resulting ether product. The properties of ethanol, such as its ability to act as a nucleophile, make it a suitable candidate for such dehydration reactions. When ethanol is heated in the presence of a strong acid, it can undergo dehydration to form ethers, which are used in various applications like solvents or anesthetics.

Sulfuric Acid

Sulfuric acid (\( ext{H}_2 ext{SO}_4\)) is known for its strong dehydrating properties, which makes it an ideal catalyst for facilitating dehydration reactions, including the formation of ether from alcohols. As a catalyst, sulfuric acid helps speed up the reaction without being consumed in the process. Its role involves protonating the alcohol, thereby making it a better leaving group and facilitating the removal of water. However, the strength and concentration of sulfuric acid mean that reaction conditions need to be closely monitored. If the temperature is too high, sulfuric acid can lead to side reactions, converting the alcohol into an alkene instead, or causing further side reactions. Its dual role emphasizes the need for careful control over the reaction environment to ensure successful ether production.

Optimal Temperature for Reactions

Reactions like the dehydration of alcohols are highly dependent on temperature. The optimal temperature range is critical for ensuring the desired product is formed. For producing ether from ethanol in the presence of sulfuric acid, the optimal temperature is around \(413 \text{ K}\). Why is temperature so crucial? If the temperature is set too low, the reaction may be too slow or incomplete, failing to yield a significant amount of ether. On the other hand, temperatures that are too high might lead to unwanted side reactions, such as the formation of alkenes. Therefore, maintaining the right temperature ensures that the ethereal reaction mechanism is favored, allowing the efficient production of ether with minimal by-products. Understanding the balance of reaction conditions illuminates why such specific temperatures are prescribed.