Question

Describe an experiment to show that ammonia diffuses faster than hydrogen chloride
​

Answer 1

Answer:

Equipment

Eye protection (goggles)

Access to a fume cupboard

Protective gloves (preferably nitrile)

A length of glass tube about half a metre long with an inside diameter of about 2 cm (note 1)

Retort stands with bosses and clamps x2

Small wads of cotton wool x2

Bungs x2 (to fit into the ends of the glass tube)

Strip of universal indicator paper (optional)

Notes:

It is very important that the tube is clean and completely dry for this experiment. If necessary, the tube can be dried by pushing a cotton wool pad soaked in acteone through the tube and leaving it for a few minutes.

The concentrated hydrochloric acid and the 880 ammonia solution are easier to handle in small bottles than in Winchesters (large bottles) for this demonstration

Procedure:

Working in the fume cupboard, clamp the glass tube at either end, ensuring that it is horizontal.

Open the bottle of ammonia solution cautiously, pointing the bottle away from both you and the audience. Open the bottle of hydrochloric acid and hold the stopper near the mouth of the ammonia bottle. Note the white clouds of ammonium chloride that form.

Put one of the cotton wool wads in the mouth of the ammonia bottle and carefully invert it to soak one side of it. Push the soaked end into one end of the glass tube. Replace the lid on the bottle.

Repeat this procedure quickly with a second wad of cotton wool and hydrochloric acid. Put the cotton wool wad into the other end of the glass tube.

Putting bungs into the ends of the glass tube will reduce the quantity of the gases which escape and therefore the smell. Once assembled, the tube can be removed from the fume cupboard.

Watch the tube and observe a ring of white powder forming near the middle of the tube. This is ammonium chloride.