Smoke without fire

Smoke without fire:

As result of reaction of acid with a base, salt is forced this
 can be chemically given in the formulae. you can conduct this
simple experiment.

smoke

HCL+NH3=NH4CL
(smoke without fire)

Materials you need are:

two cotton swabs, dipped in HCL and NH3 solution respectively,
One open ended glass tube with 25cm long and 10 mm diameter ,
a black screen.

Procedure dip one cotton swab in strong HCL solution and place
it towards the one end of the glass tube, meanwhile dip another
cotton swab into NH3 and place it to the another end of the tube
wait for 5 minutes. You can observe white rings like smoke rings
are formed near the HCL side; this is because HCL ammonia gas
travels faster then HCL fumes

       To continue this interesting experiment you can take 2
drops of HCL in a glass and two drops of NH3 in a saucer, when you place
saucer over the glass

White smoke will appear, it happens for sometime, you will be
shocked to see smoke without fire this happens as the reaction
takes between HCL Hydrochloric acid and liquid ammonia NH3. While
doing this experiment if you have black screen behind the smoke
appears great.