IIT JEE Chemistry Questions 23. Alkynes

Preparation, properties and reactions of alkynes:

Physical properties of alkynes (boiling points, density and dipole moments);
Acidity of alkynes;
Acid catalysed hydration of alkynes (excluding the stereochemistry of addition and elimination);

Reduction of alkynes;
Preparation of alkynes by elimination reactions;
Addition reactions of alkynes;
Metal acetylides.


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On methods of preparation

1. what is produced by hydrolysis of Calcium carbide?
2. What is produced by hydrolysis of magnesium carbide?
3. Name the potassium salt used to produce acetylene in Kolbe's electrolytic method.
4. what is the first stage in dehydrohalenation of vicinal dihalides and what are the conditions required for the reaction?
5. what is the second stage in dehydrohalenation of vicinal dihalides and what are the conditions required for the reaction?
6. what do you get in the first stage after reaction of 1,1 -dibromopentane with KOH(alc)?
7. How do you get ethyne from iodoform?
8. How do you get ethyne from chloroform?
9. what do you get by hydrolysis of Aluminium carbide?
10. which gaseous hydrocarbon is produced when calcium carbide reacts with water?


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Simple questions on reactions of Alkynes

1. When propyne is treated with acqeous H-2SO-4 in the presence of HgSO-4, which ketone is formed?
2. Which hydrocarbon contains acidic hydrogen?
3. Give bases stronger and weaker acetylene?
4. Give acids stronger than and weaker than acetylene?
5. To add water to a triple bond what other chemicals are required?
6. When R’MgBr reacts with RC- triple bond-CH, what alkane will result?
7. What are the products of ozonolysis of triple bond (alkyne)?
8. What is the output when ethyne is passed through hot iron tube at 400 degrees Celsius?
9. What is Lindlar’s catalyst?
10. Which alkene will emerge when alkyne is reduced with Lindlar’s catalyst?
11. Which alkene will emerge when alkyne is reduced with lithium metal in liquid ammonia solvent?
12. Among alkynes and alkenes, which are more reactive to halogens? Why?
13. What is the product obtained by adding water to 1-butyne in the presence of required catalysts? What are the catalysts?
14. What are tautomers?
15. What is final the output of polymerization of acetylene? What are intermediate outputs?
16. What are alkadienes?
17. What do you get by adding H-2 to 2-butyne? Give the two alternatives due to difference in reducing agents.

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