An experiment in the laboratory

A laboratory method for the preparation of hydrogen chloride solution. Hydrogen chloride is most conveniently prepared in the laboratory by combining concentrated sulphuric acid and sodium chloride and then heating the mixture. We place the sodium chloride in the flask and the sulphuric acid is slowly added through the funnel. The flask is heated with a small flame. The reaction of the sulphuric acid and the sodium chloride yields sodium hydrosulphate and hydrogen chloride as represented by the equation

NaCl + H₂S0₄ → NaHS0₄ + HC1. The hydrogen chloride gas is collected in the first bottle as it displaces the air. When the bottle is filled, the gas will continue on to pour into the second bottle where it dissolves in water and forms hydrochloric acid.

A laboratory method of preparing hydrogen. The usual laboratory method of preparing hydrogen is to replace the hydrogen in an acid by a metal. For example, if a metallic zinc is mixed with dilute hydrochloric acid, the zinc replaces the hydrogen in the hydrochloric acid (hydrogen chloride). This action produces zinc chloride and hydrogen as shown in the following equation:

Zn + H₂S0₄ → ZnS0₄ + H₃

A small amount of granulated zinc is placed in the bottle. Dilute hydrochloric acid is poured into the bottle through the tube. The hydrogen which is freed passes through delivery tube to the collecting bottle.