Humboldt State University ® Department of Chemistry

Robert A. Paselk Scientific Instrument Museum

 
From: Noyes, William A. A Textbook of Chemistry. Henry Holt and Company, New York (1919) pp 53-4
 
©Richard A. Paselk 1998
 

 

 

Apparatus for the Preparation of Hydrogen. In the laboratory, small quantities of hydrogen may be generated in the simple apparatus shown in Fig. 14. Zinc and some water are placed in the generating flask, and dilute sulfuric acid* is added in portions through the thistle tube.
 
* As sulfuric acid is heavier than water (sp. gr. 1.84) and much heat is generated on its dilution, it should always be poured slowly into water and should never be diluted by pouring water upon the acid. Pouring water on concentrated sulfuric acid may cause an explosion.
 
A more convenient apparatus for the preparation of larger amounts, or when it is desired to have the gas always ready for use, is the Kipp generator (Fig. 15). The zinc is placed in the middle bulb and the dilute acid is poured in through the upper bulb, which communicates with the lower one through the tube A. When the stopcock B is opened, the acid rises and comes in contact with the zinc in the middle bulb and the generation of hydrogen begins. Whenever the stopcock is closed the hydrogen generated forces the acid away from the zinc and the action ceases as soon as the acid moistening the surface of the zinc is exhausted. The generator is not altogether satisfactory because the spent acid containing zinc sulfate is mixed with that which has not been used, diluting it and causing the action to become very slow before the acid has been exhausted.
 


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Last modified 22 July 2000