the experiment in the lab, often hard to avoid can produce excess ammonia, so should be how to deal with excess ammonia?
What does ammonia gas use to absorb better?
The first way is to pass ammonia into saturated salt water, that is, saturated NaCl solution, which is better than directly into water absorption effect, because the solubility of ammonia in saturated salt water is higher than that in water, this is to take advantage of the easy solubility of ammonia in water, that is, the physical properties of ammonia.
The second method is to pass ammonia gas into a “U” tube or drying tube containing calcium chloride. This is to take advantage of the fact that ammonia gas can react with calcium chloride to form octalamine calcium chloride, which is the chemical nature of ammonia gas. Therefore, calcium chloride can not be used as a desiccant when drying ammonia gas, and this is why.
Of course, if it is the exhaust gas treatment in the laboratory, with acidic solutions such as sulfuric acid, you can completely dispose of ammonia.