Hydrogen Chloride Gas from Salt and Sulphuric Acid

Hydrogen chloride is the gas that makes hydrochloric acid when it dissolves in water. Sulphuric acid drives it out of common salt. This is the laboratory way the 1907 US Dispensatory gives: fused salt in a flask on a sand bath, sulphuric acid equal to its weight and diluted with a third of its weight of water let in slowly, then gentle heat. Here the gas is led off to be used (in the Dispensatory it is dissolved in water bottles). The picture: our diagram.