Common Acid-Base Indicators                             Family of Salt
Indicator         pH range   Acid       Base                Salts having common acidic or basic
Thymol Blue         1.2-2.8  red        yellow               radicals are said to belong to same family.
Methyl yellow       2.9-4.0  red        yellow
Methyl orange       3.1-4.4  red        orange              Sodium chloride (NaCl) and Calcium
Bromphenol          3.0-4.6  yellow     blue-violet          chloride (CaCl2) belong to chloride family.
blue                                                        Calcium chloride (CaCl2) and calcium
Methyl red          4.4-6.2  red        yellow               sulphate (CaSO4) belong to calcium
Phenol red          6.4-8.0  yellow     red                  family.
Neutral red         6.8-8.0  red        yellow
Phenolphthalein    8.0-10.0  colorless  red                 Zinc chloride (ZnCl2) and Zinc sulphate
Nile blue         10.1-11.1  blue       red                  (ZnSO4) belong to zinc family.
Nitramine         11.0-13.0  colorless  orange red
                                                        Characteristics of salt
Litmus Paper or Solution                                1.   Most of the salts are crystalline solid
                                                        2.   Salts may be transparent or opaque
    This indicator is present in two colors: red       3.   Most of the salts are soluble in water
     and blue.                                          4.   Solution of salts conducts electricity. Salts
    Blue litmus paper or solution is used to                conduct electricity in their molten state
     test a substance for acidity.                           also
                                                        5. The salt may be salty, sour, sweet, bitter
    Red litmus paper or solution is used to test
                                                             and umami (savoury)
     a substance for alkalinity.                        6. Neutral salts are odourless
    Indicates    Litmus          Litmus
                 Paper turns     Solution turns         Acidic, Basic and Neutral Salts
    In Acid      red             red
    In Base      blue            blue                   Acidic salt: Salts which are formed after the
    In Neutral   Color does      purple                 reaction between a strong acid and weak base
                 not change                             are called acidic salt. The pH value of acidic
                                                        salt is lower than 7. e.g. ammonium sulphate,
                                                        ammonium chloride, etc.
Salts
                                                        Basic Salt: Salts which are formed after the
Salts are the ionic compounds which are
                                                        reaction between weak acid and strong base
produced after the neutralization reaction
                                                        are called basic salt. The pH value of a basic
between acid and base.
                                                        salt is more than 7. e.g. sodium carbonate,
Salts are electrically neutral.                         sodium acetate, etc.
Sodium chloride (NaCl) is also known as table           Neutral Salt: Salts produced because of
salt or common salt.                                    reaction between strong acid and strong base
                                                        are neutral in nature. The pH of value of such
                                                        salts is equal to 7, i.e. neutral. e.g. Sodium
                                                        chloride, sodium sulphate, potassium chloride,
                                                        etc.
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