Hydrogen chloride fountain experiment

FIG. 13-4. The hydrogen chloride fountain the same experiment can be carried out with ammonia instead of hydrogen chloride. 

The reaction between HCl gas and water makes hydrogen chloride extremely soluble in water (see the fountain experiment, page 186). A considerable amount of heat is also given out, although this is quickly absorbed by the water. 

Very soluble gases (such as ammonia and hydrogen chloride) can be made to perform the fountain experiment . Figure 11.9 shows the experiment carried out with HCl(g). A flask is fitted with a cork and tube and filled with dry hydrogen chloride. Without delay, the flask is lowered into a deep bucket of water. So much gas dissolves in the water rising up the tube that a partial vacuum is created in the flask. This draws... 

Hydrogen chloride is so soluble in water that you can do the fountain experiment with it (page 156). 

Figure 6.7 The famous fountain experiment illustrates both the very high solubility of hydrogen chloride in water, and the fact that the solution is acid, (a) An inverted flask full of HCl is connected by a tube to a reservoir containing water coloured by blue litmus. By blowing down the auxiliary tube, this water is forced up the connecting tube into the upper flask containing HCl. (b) Because HCl is so soluble, the first drops of water dissolve the contents of the flask, leaving a vacuum, (c) Water then fountains in without further assistance, filling the vacuum and the flask and turning red as it does so because of the acidity of the solution and the presence of litmus.

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