Physical Properties of Ethyne by keypoint It is sparingly soluble in water. It is less dense than air It is a colourless gas with a sweet smell when not impure. It is unstable and may explode when compressed to a liquid. Others are Viewing: Chemical Properties of Ethyne Ethyne Uses of Ethyne Physical properties of Methane Physical Properties of Ethanol Physical Properties of Ethanoic Acid Physical Properties of Ethyl Ethanoate