Learning outcome:
- Bleaching powder, its preparation, uses, the technique of removing colour spot, and killing germs
- Glass cleaner, its preparation, uses, and technique of cleaning glass
- Laboratory and industrial preparation of ammonia gas
Bleaching Powder
The chemical name of bleaching powder is Calcium oxychloride (Ca(OCl)Cl).
Uses
- To remove or make colourless the ink of ball-pen of any other colour which cannot be removed from clothes by detergent or soap
- For killing germs on floor, commode, basin etc
Preparation
Bleaching powder is produced when Chlorine gas is passed through the Calcium Hydroxide at 40°C temperature.
The technique of removing colourful spot on clothes
Bleaching powder makes the colourful spots of clothes colourless. This is why it is called an anti-pigment.
We know spot of clothes and bleaching powder both are chemical substances. When we add water to bleaching powder after putting it on the dirt spot of clothes then bleaching powder reacts with water to produce calcium chloride (CaCl2) and hypochlorus acid (HOCl).
HOCl then breaks up and produces HCl and nascent oxygen [O]
Nascent oxygen [O] reacts with colourful material and makes the colourful materials colourless.
The technique of killing germs by bleaching powder
Bleaching powder is used to kill germs on house floor, commode, basin etc. When water is added to bleaching powder after putting the powder on floor, commode, basin etc, bleaching powder reacts with water and turns into calcium chloride (CaCl2) and hypochlorus acid (HOCl).
Hypochlorus acid breaks up to produce nascent oxygen [0] which kills germs.
Related: Washing Soda and Toilet Cleaner
Glass Cleaner
The detergent which is used for cleaning glass is called glass cleaner.
Uses
When there is oil, fat or grease on glass, they attract dust and makes dirt on glass. Here, the cleaning material which reacts with oil, fat or grease to clean the glass but does not react with sodium silicate or calcium silicate, an element of glass.
Preparation
Glass cleaner is usually prepared by mixing isopropyl alcohol (CH3CH(OH)CH3) with NH4OH (ammonia solution) which is prepared by dissolving ammonia gas in water.
The technique of cleaning the glass with glass cleaner
When we apply glass cleaner on glass, NH4OH reacts with oil, fat or grease on the glass and removes them from the glass. If there is an organic substance on the glass, isopropyl alcohol dissolves organic substance and removes it from the glass.
Precaution
We should use the mask on mouth and nose while cleaning glass with glass cleaner. Because the ammonium hydroxide of the glass cleaner may enter our nose and mouth to harm our body.
Laboratory Production of Ammonia Gas
We can generally produce ammonia gas in the laboratory in two ways.
- Ammonia is produced in the laboratory by mixing and heating ammonium chloride (NHCl4) and calcium oxide (CaO) in a test-tube.
- Ammonia gas, calcium chloride and water are produced when ammonia chloride and slaked lime Ca(OH)2 are mixed and heated in a test-tube.
Industrial Production of Ammonia Gas
Ammonia gas is produced by Heber process in industries. This process involves by mixing N2 and H2 gases at the ratio of 1:3 and heating the mixture at (450- 550)°C temperature after adding Fe catalyst. Some heat is also produced while producing ammonia gas. This is an exothermic reaction.
In one side, N2 and H2 react and produce NH3. On the other side, some NH3 gases break up and turn into N2 and H2 gases. This is an equilibrium reaction.
Reference- NCTB Books and Wikipedia
