Hydrogen Laboratory Preparation

A sample of hydrogen gas may be prepared in the lab by the action of dil hydrochloric acid on magnesium ribbon. (CAUTION - Danger of Explosion and severe personal injury. Ensure there are no naked flames if the reaction is done on any scale greater than a single test tube.) This clip shows the use of a thistle funnel. On adding acid solution the acid solution must cover the bottom of the funnel down tube. (Caution - Danger of glass cuts. Make sure you know how to fit glassware to bungs. ) Thistle funnels used in this way provide a indication of the pressure in the reaction flask by the level of acid in the down tube of the funnel. Tap funnels do not warn the user of an unwanted build up of pressure in the reaction flask. If a sample of hydrogen collected in a test tube is very pure (the reaction is allowed to run to flush out any air before the collection) and 'tested' by a lighted flame, the 'pop' is never squeaky, and is rather disappointing. See ChemPics 'Testing for Hydrogen'.

Category:

Education

Tags:

• hydrogen
• collection
• preparation
• laboratory
• lab