The correct answer to the question is **C. diethyl sulphate**. Let's break down the reasoning behind this answer step-by-step. ### Explanation of the Correct Answer (C. diethyl sulphate) 1. **Understanding the Reaction Conditions**: - The question states that excess ethanol is heated to 145 °C in the presence of concentrated sulfuric acid. This is a crucial detail because the temperature and the presence of sulfuric acid will dictate the type of reaction that occurs. 2. **Role of Concentrated Sulfuric Acid**: - Concentrated sulfuric acid acts as a dehydrating agent. When mixed with ethanol, it can facilitate the formation of ethyl sulfate through a process called esterification. In this case, the sulfuric acid protonates the ethanol, making it a better leaving group. 3. **Formation of Diethyl Sulfate**: - The reaction can be summarized as follows: - Ethanol (C₂H₅OH) reacts with sulfuric acid (H₂SO₄) to form ethyl hydrogen sulfate (C₂H₅OSO₃H). - When heated, this intermediate can further react with another molecule of ethanol to produce diethyl sulfate (C₂H₅)₂SO₄ and regenerate sulfuric acid. - The overall reaction can be represented as: \[ 2 \text{C}_2\text{H}_5\text{OH} + \text{H}_2\text{SO}_4 \rightarrow \text{(C}_2\text{H}_5\text{)}_2\text{SO}_4 + \text{H}_2\text{O} \] ### Why the Other Options are Incorrect - **A. Diethyl Ether**: - Diethyl ether (C₂H₅)₂O is formed through a different reaction mechanism known as dehydration of ethanol. This typically occurs at lower temperatures (around 140 °C) and requires a different stoichiometry and conditions. In the presence of concentrated sulfuric acid and at higher temperatures, the formation of diethyl ether is less favored compared to diethyl sulfate. - **B. Ethyne**: - Ethyne (C₂H₂), also known as acetylene, is produced from the dehydrohalogenation of alkyl halides or from the pyrolysis of hydrocarbons. Ethanol does not directly convert to ethyne under the conditions described. Therefore, this option is not relevant to the reaction taking place. - **D. Acetone**: - Acetone (C₃H₆O) is a ketone that can be produced from the oxidation of isopropanol or through other specific reactions. Ethanol does not convert to acetone under the influence of sulfuric acid and heat. Thus, this option is also incorrect. ### Summary of Key Points - **Reaction Conditions**: Excess ethanol heated with concentrated sulfuric acid at 145 °C leads to the formation of diethyl sulfate. - **Role of Sulfuric Acid**: Acts as a dehydrating agent, facilitating the formation of ethyl hydrogen sulfate and subsequently diethyl sulfate. - **Incorrect Options**: Diethyl ether, ethyne, and acetone are not produced under the given conditions. ### Revision Summary - The correct product of heating excess ethanol with concentrated sulfuric acid at 145 °C is diethyl sulfate (C₂H₅)₂SO₄. - Concentrated sulfuric acid acts as a dehydrating agent, promoting esterification. - Diethyl ether, ethyne, and acetone are not formed under these specific conditions. - Understanding reaction mechanisms and conditions is crucial for predicting products in organic chemistry.