Properties of acids and bases

Properties of acids and bases

Properties of acids and bases: The classification of substances into acid and base is according to some of their characteristics.

how can you tell an acid from a base

We can classify properties of acid and base
1.Physical methods
2.Chemical methods

Physical Properties Acids and Bases

The substances that taste sour are called as acid. For example lemon juice, tomato, curd.
The substances that taste bitter are called as base.For example soap, lime water containing calcium hydroxide, house cleaners.

Some Naturally occurring acids

 Vinegar                     – Acetic Acid
 Orange                      – Citric Acid
 Lemon                      – Citric Acid
 Tamarind                  – Tartaric Acid
 Tomato                      – Oxalic Acid
 Sour milk (Curd)       – Lactic Acid
 Ant and Nettle sting          – Methanoic Acid

Acid-Base Indicators

             Name of the                             Colour Change                             Colour Change
                Indicator                                   withAcid                                        with Base

A.      Blue litmus solution                          To red                                          No change
B.      Red litmus solution                            No change                                   To blue
C.      Turmeric                                             No change                                   To red
D.      Methyl orange                                    To red                                          To yellow
E.      Phenolphthalein (colourless)               No change                                  To pink

Chemical Properties of Acids and Bases

1. Acid + Metal → Salt + Hydrogen

Pop test : When a burning candle is brought near a test tube containing hydrogen gas it burns with a ‘Pop’ sound. This test is conducted for examining the presence of hydrogen gas.

2. Base + Metal→ Salt + Hydrogen
      Note – Such reactions are not possible with all the metals.

3. Action of Acids with metal Carbonates and metal bicarbonates

Metal Carbonate + Acid → Salt + Carbondioxide + Water

4. Acids or bases in a Water Solution

   Acids produce H+ions in the presence of water
   Bases provide (OH–) ions in the presence of water

5. Reaction of Non Metallic Oxide with Base
     Non metallic oxide + Base →  Salt + Water

6.Reactions of metal oxides with acids

   Metal Oxide + Acid → Salt + Water

7. Neutralization Reactions 

     Base + Acid→ Salt + Water
 While studying remember "properties of Acids and Bases" all bases do not dissolve in water. An alkali is a base that dissolves in water. Common alkali's are NaOH Sodium hydroxide KOH Potassium hydroxide

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