Alkalis are used as cleaning agents in the form of liquids and powders. They are particularly useful in the laundry. Very strong alkalis should be used with the utmost caution as they are corrosive and toxic. These are called caustic alkalis. Many alkalis act as bleaches. Caustic soda based cleaning agents are used to clear blocked drains and to clean ovens and other industrial equipment. Ammonia is a strong grease emulsifier and should also be carefully used as it emits strong fumes. It is also added to abrasive formulations. Toilet cleaners to which bleach has been added are very effective. It should be kept in mind that sodium chlorite bleach should never be used with an acidic toilet cleaner, however, as it will release toxic chlorine gas.
The
use of alkalis in cleaning is summarized in below table
|
Acid |
pH |
Uses |
|
Sodium
hydroxide(caustic soda) |
14 |
Removing
stubborn grease from ovens and equipment. Clearing blocked drains. |
|
Ammonia |
11 |
Removing
stubborn grease. |
|
Sodium
carbonate(washing soda) |
10 |
Used
as an alkaline builder in synthetic and soapy detergents. Clearing blocked
drains. |
|
Sodium
perborate |
10 |
Removing
stains and whitening due to bleaching action at higher temperatures (above 40o) |
|
Sodium
hypochlorite |
9 |
Removing
stains and whitening due to bleaching action on various types of surfaces. Acts
as disinfectant. |
|
Sodium
bicarbonate(baking soda) |
8 |
Removing
stubborn grease from smooth, delicate surfaces. Removing
stains such as tea,coffee and fruit juice. |
|
Sodium
pyroborate (borax) Sodium
thiosulphite |
8 7 |
Same
as above. Removing
iodine stains. |