PDF chapter test TRY NOW
There are common tests we use to identify a salt.
- Physical examination of the salt
- Dry heating test
- Flame test
Physical examination: The test involves the colour, smell and density of the salt. This test is not really accurate.
Dry heating test: A small amount of salt is heated in a dry test tube for this test. The dissolved salts settle in the container after all the water has evaporated.
![shutterstock_714036457.jpg](https://resources.cdn.yaclass.in/f909da7f-3b1e-4484-a724-b84e17f75f81/shutterstock714036457w300.jpg)
Test for dry heating
Flame test: When certain salts react with concentrated hydrochloric acid (\(HCl\)), their chlorides are formed. With the help of platinum wire, the mixture of concentrated \(HCl\) paste is added to the flame.
![shutterstock_24894655.jpg](https://resources.cdn.yaclass.in/d5d37409-969a-44e8-bec3-054087ab32a5/shutterstock24894655w300.jpg)
Flame test
![shutterstock_155936723.jpg](https://resources.cdn.yaclass.in/0d50757b-0678-41be-95a4-d4e1a58894b4/shutterstock155936723w300.jpg)
Inference and colour of the flames
Uses of salts
There are some salts that we use in daily life. They are listed below with their chemical names.
Chemical Name | Chemical formula | |
Common salt | Sodium chloride | \(NaCl\) |
Washing soda | Sodium carbonate | \(Na_2CO_3\) |
Baking soda | Sodium bicarbonate or sodium hydrogen carbonate | \(NaHCO_3\) |
Bleaching powder | Calcium oxychloride | \(CaOCl_2\) |
Plaster of Paris | Calcium sulphate hemihydrate |
Common salt:
- It is a popular food preservative and flavour enhancer in the food industry.
- It is a key ingredient in producing chemicals like sodium carbonate and sodium hydrogen carbonate in the industrial sector.
- It is used in cold countries to prevent the formation of ice on highways, bridges and other surfaces, which is essential for safe driving conditions.
Washing soda:
- It is used in softening hard water.
- It is used in soap, glass and paper industries.
- It is used for removing a wide range of stains such as grease, blood, tea and coffee stains.
- It is used in textile industries to help dyes adhere to the fabric.
- It can be used in bathrooms to remove soap scum and around the house for general cleaning of hard surfaces.
Baking soda:
- It is used to treat stomach upset and indigestion by lowering stomach acidity.
- It is used in the making of baking powder.
- It is used in fire extinguishers (foam extinguishers) along with aluminium sulphate.
- It is used to make cakes and bread, soft and spongy.
- It is used in ear drops, cosmetics and personal care products.
- It acts as a neutraliser for the effect of acid.
Bleaching powder:
- It is used in the laundry industry for bleaching cotton and linen.
- It is used as a disinfectant in the drinking water supply.
- Since it acts as a strong oxidising agent, used in many industries.
Plaster of Paris:
- It is used in the plastering of bones.
- It is used in the production of statue casts.
- It is a component of chalk.
- It is used in the construction of a false ceiling.