Question

Ethylene forms ethylene chlorohydrin by the action of (1) dry chlorinc gas (2) dry hydrogen chloride gas (3) solution of chlorine gas in water (4) dilute hydrochloric acid

Short answer

(3) solution of chlorine gas in water

Step-by-step solution

Understand the Reaction

Ethylene (C2H4) reacts with chlorine to form ethylene chlorohydrin. The correct reagent needs to provide both Cl and OH groups.

Evaluate Dry Chlorine Gas

Dry chlorine gas (Cl2) does not provide a source of OH groups, so it is not the correct reactant.

Evaluate Dry Hydrogen Chloride Gas

Dry hydrogen chloride (HCl) gas also does not provide a source of OH groups, making it an unsuitable reactant for this reaction.

Evaluate Solution of Chlorine Gas in Water

A solution of chlorine gas in water forms hypochlorous acid (HOCl), which can provide both Cl and OH groups needed for the formation of ethylene chlorohydrin.

Evaluate Dilute Hydrochloric Acid

Dilute hydrochloric acid (HCl) does not form a source of OH groups directly, so it is not suitable.

Conclusion

The solution of chlorine gas in water is the correct reagent that provides both Cl and OH groups.

Key concepts

chemical reactions

Chemical reactions are processes where one or more substances are converted into new substances. This conversion happens through the breaking and forming of chemical bonds. To understand how ethylene forms ethylene chlorohydrin, consider the reactants and products.

For this specific reaction, ethylene reacts with chlorine in the presence of water to produce ethylene chlorohydrin. Chlorine serves as the source of Cl (chlorine) atoms and water as the source of OH (hydroxyl) groups.

Breaking down this reaction step-by-step helps in identifying that a direct supply of both Cl and OH groups is crucial for forming ethylene chlorohydrin. Thus, understanding which chemical reactions and conditions provide these essential groups is key to determining the right reagent.

organic chemistry

Organic chemistry is the branch of chemistry that deals with compounds mainly composed of carbon and hydrogen. Ethylene (C2H4) is a simple organic molecule consisting of two carbon atoms double-bonded to each other, each attached to two hydrogen atoms.

Its double bond makes ethylene highly reactive, particularly with halogens (like chlorine) and other molecules, to form various derivatives such as ethylene chlorohydrin. Organic reactions often involve the functionalization of the carbon-hydrogen framework with other atoms or groups.

For example, the formation of ethylene chlorohydrin needs the introduction of chlorine (Cl) and hydroxyl (OH) groups to the ethylene molecule. In organic synthesis, understanding the reactivity of different functional groups and the conditions they require is essential to predict and control chemical transformations.

reagents

Reagents are substances used in chemical reactions to test for, measure, examine, or produce other substances. Choosing the correct reagent is crucial for the success of any chemical reaction.

In the case of forming ethylene chlorohydrin, the correct reagent must provide both chlorine (Cl) and hydroxyl (OH) groups. Here’s how different reagents are evaluated:

• Dry chlorine gas (Cl2): Lacks OH groups, making it unsuitable.
• Dry hydrogen chloride gas (HCl): Also lacks OH groups, making it unsuitable.
• Solution of chlorine gas in water: Forms hypochlorous acid (HOCl), providing both Cl and OH groups, making it the correct reagent.
• Dilute hydrochloric acid: Does not provide OH groups directly, making it unsuitable.

Thus, the solution of chlorine gas in water is the optimal reagent for this reaction as it fulfills the requirement of providing both functional groups necessary for the desired product.