Chapter 10: Problem 37

Give the two reactions of acetylene which are used to distinguish it from alkenes.

Short Answer

Expert verified

The two characteristic reactions of acetylene that distinguish it from alkenes are: 1. Formation of a white precipitate with ammoniacal silver nitrate solution (Tollens' reagent). The reaction is: 2AgNO₃ + 2NH₄OH + C₂H₂ -> Ag₂C₂ ↓ + 2NH₄NO₃ + 2H₂O 2. Formation of a reddish-brown precipitate with cuprous chloride solution (Cu₂Cl₂) in the presence of ammonia. The reaction is: 2CuCl + C₂H₂ + 4NH₄OH -> Cu₂C₂ ↓ + 4NH₄Cl + 2H₂O + 2NH₃

Step by step solution

Reaction 1: Formation of Precipitate with Ammoniacal Silver Nitrate Solution

To test for the presence of acetylene, pass the gas through an ammoniacal silver nitrate solution (Tollens' reagent). If the gas is acetylene, a white precipitate of silver acetylide (Ag₂C₂) is formed, which is not observed with alkenes as they don't react with ammoniacal silver nitrate solution. The reaction is as follows: 2AgNO₃ + 2NH₄OH + C₂H₂ -> Ag₂C₂ ↓ + 2NH₄NO₃ + 2H₂O

Reaction 2: Formation of Reddish Brown Precipitate with Cuprous Chloride Solution

To further distinguish acetylene from alkenes, pass the gas through a cuprous chloride solution (Cu₂Cl₂) in the presence of ammonia. A reddish-brown precipitate of copper acetylide (Cu₂C₂) is formed when acetylene reacts with the cuprous chloride solution, whereas alkenes do not produce any precipitate in this reaction. The reaction is as follows: 2CuCl + C₂H₂ + 4NH₄OH -> Cu₂C₂ ↓ + 4NH₄Cl + 2H₂O + 2NH₃ These two reactions are characteristic of acetylene and help in distinguishing it from alkenes.

Unlock Step-by-Step Solutions & Ace Your Exams!

Full Textbook Solutions
Get detailed explanations and key concepts
Unlimited Al creation
Al flashcards, explanations, exams and more...
Ads-free access
To over 500 millions flashcards
Money-back guarantee
We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Give the two reactions of acetylene which are used to distinguish it from alkenes.

Short Answer

Step by step solution

Reaction 1: Formation of Precipitate with Ammoniacal Silver Nitrate Solution

Reaction 2: Formation of Reddish Brown Precipitate with Cuprous Chloride Solution

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Chemistry Textbooks

Inorganic Chemistry

Nuclear Chemistry

Ionic and Molecular Compounds

Chemistry Branches

Chemical Reactions

The Earths Atmosphere

Study anywhere. Anytime. Across all devices.