Leaving Certificate Chemistry Organic Chemistry 12 – Ethyne Leaving Certificate Chemistry

Carbon-Carbon triple bond The Alkynes: CnH2n - 2 Ethyne: C2H2 Carbon-Carbon triple bond 2 Carbons Longest Chain H C C H 2 planar carbons

The Alkynes - Ethyne

Mandatory Experiment Preparation of Ethyne

Acidified Copper Sulfate Solution CuSO4 Preparation of Ethyne Calcium Dicarbide CaC2 Water H2O Acidified Copper Sulfate Solution CuSO4 Water added to calcium dicarbide produces ethyne gas with impurities. These impurities are removed by passing them through acidified copper sulfate solution.

Preparation of Ethyne

Impurities Calcium dicarbide Calcium sulfide solid Hydrogen sulfide gas Phosphine gas Calcium phosphide solid Calcium dicarbide

Preparation of Ethyne The first couple of test tubes collected are usually discarded as they contain displaced air from the reaction boiling tube.

Balanced Equation for the Synthesis of Ethyne Preparation of Ethyne Balanced Equation for the Synthesis of Ethyne CaC2 + H2O 2 C2H2 + Ca(OH)2 Water Ethyne Calcium Dicarbide Calcium Hydroxide

Preparation of Ethyne 10

Ethyne reaction with acidified potassium permanganate When ethyne gas is bubbled through a solution of acidified potassium permanganate solution a colour change from pink to colourless is observed. This proves that ethyne is an unsaturated compound.

Ethyne reaction with bromine water When ethyne gas is bubbled through a solution of bromine water, colour change from yellow to colourless is observed. This proves that ethyne is an unsaturated compound.

Ethyne Combustion Reaction Preparation of Ethyne Ethene is Ethyne Combustion Reaction Balanced Equation for the Combustion of Ethyne C2H2 + 2½ O2 2 CO2 + H2O Turns blue cobalt chloride paper pink Turns Limewater Milky

Oxy-acetylene Flame for cutting metals Uses of ethyne Oxy-acetylene Flame for cutting metals Fuel for Carbide Lamps

So far in organic chemistry