Study notes on "ACIDS AND BASES"

ACIDS AND BASES


ACIDS

  • It comes from the Latin word "acidus", which means "sharp" or "sour". 
  • A solution that has an excess of H+ ions. 
  • It loses its acidity when they are combined with alkalies.
  • Strong Acids are dangerous and can burn your skin.
  • It changes the colour of LITMUS :
                         Blue ---> Red 


Examples of Acids:

1. Vinegar 
3. Citrus Fruits 
2. Stomach Acid (HCl)
Strong Acid:
The pH value is below 3.
A strong acid is one which is virtually 100% ionised in solution.

Weak Acid: 
An acid that only partially ionizes in an aqueous solution. This means that not every molecule breaks apart. Weak acids usually have a pH close to 7 (3-6). 

BASES

  • A solution that has an excess of OH- ions. 
  • Another word for base is "alkali".
  • It feels slippery.
  • It become less alkaline when they are combined with acids.
  • It changes the colour of litmus:
                            Red --- >  Blue

Examples of Bases:
1. Sodium hydroxide(NaOH, strong base)
2. Ammonia

Strong Base: 
The pH value is above 10.

Weak Base: 
A base that only partially ionizes in an aqueous solution. This means that not every molecule breaks apart. Weak bases usually have a pH close to 7 (8-10). 
Common Acids
Acetic acid                                   : vinegar, acetate
Acetylsalicylic acid                     : aspirin
Ascorbic acid                              : vitamin C
Carbonic acid                             : soft drinks, seltzer water
Citric acid                                   : citrus fruits, artificial flavorings
Hydrochloric acid (HCl)           : stomach acid
Nitric acid                                   : fertilizer, explosives
Sulfuric acid                               : car batteries

Common Bases
Aluminum hydroxide              : antacids, deodorants
Ammonium hydroxide            : glass cleaner
Calcium hydroxide                  : caustic lime, mortar, plaster
Magnesium hydroxide             : laxatives, antacids
Sodium bicarbonate/sodium hydrogen carbonate : baking soda
Sodium carbonate                   : dish detergent
Sodium hydroxide                   : lye, oven and drain cleaner
Sodium hypochlorite               : bleach

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