1. 22nd June 2012 Alkynes
AIM – to investigate the properties of alkynes

2. Alkynes contain a triple carbon - carbon bond
They have the general formula CnH2n-2
They have the name suffix –yne with a number to indicate the position of the triple bond in the chain if necessary
For this course we only need to consider reactions of ethyne

3. Preparation of ethyne
Ethyne can be prepared from the reaction of calcium carbide and water

4. Combustion Alkynes burn in oxygen with a smoky flame
Write a balanced equation for the complete combustion of ethyne
2C2H2 + 5O2 4CO2 + 2H2O

5. Addition
Alkynes will be converted to haloalkenes by the addition of halogens or HCl
Alkynes will be converted to alkenes by the addition of hydrogen