Ammonia Level Hydrogen chloride w A length of glass tube, one end of which is drawn out into a jet – a 1 cm 3 pipette would do. The length should be such that when the tube is fitted through the stopper, the jet is near the centre of the flask and about 20 cm of tube protrudes through the stopper. w Tap funnel. w Access to a fume cupboard. w Bunsen burner or hair drier. w Length of rubber delivery tube. w One 10 cm 3 or 20 cm 3 plastic syringe. w A two-holed rubber stopper to fit the flask.