Ammonia gas is toxic and corrosive. This demo must be prepared in the hood.
Chemicals and Solutions:
Lecture bottle of anhydrous ammonia
Bromocresol purple indicator
Chem 317 tech may have lecture bottles of NH3 or HCl available (rather than storing extra bottles of this in the demo lab)
Fountain set-up, see photo
Two short pieces of amber tubing
Two pinch clamps
Vacuum grease for seals
The upper bulb of the apparatus must be DRY prior to filling with ammonia.
Carefully disassemble apparatus.
Fill the bottom flask with water and color with bromocresol indicator solution. Make the water in the flask yellow by adding dilute HCl until the solution just changes color.
Reassemble apparatus; regrease stopcocks if necessary. Make sure the joints sealed.
Attach squeeze bulb to lower side arm.
Attach amber tubing to the upper side arm.
Adjust 3-way stopcock so that the flow is from the side tube to the top.
In the hood, connect lecture bottle of ammonia and flush upper flask with plenty of gas. All air must be displaced and a certain amount of mixing of the gases must be overcome. (Do not fill more than 3 hours before intended use.)
After shutting off tank valve on lecture bottle, close the upper side arm with a pinch clamp and rotate 3-way stopcock 180 degrees such that flow is from side tube to bottom.
Remove the tubing connecting apparatus with lecture bottle.
After use, wash the entire apparatus and DRY thoroughly using acetone and air before putting away.
Turn center stopcock 90 degrees clockwise.
Squeeze bulb until liquid squirts into top flask.