A glass capillary is dipped one end into the hydrochloric acid, and then the other end into the ammonia. In each case, capillary action draws a small amount of liquid into the capillary. The capillary is placed flat against a dark surface. In just a few moments, a white solid forms inside the capillary. Use a millimeter rule to measure the distance between the boundary of each liquid in the capillary and the white solid.
Place drops of the chemicals on cotton wads set on watch glasses.
Have two students assist you. Using tweezers, insert these wads into the open ends of the glass tube. Stopper the ends. Note which end contains the ammonia. It takes 5 to 10 minutes for the reaction to take place to a noticeable extent.