Just like Acids have a sour taste, Bases have a bitter taste

 

Bases are the chemical opposite of acids. They cancel the effect of acids. Let’s define it formally.

Definition of Base

A base is a substance which furnishes hydroxide ions (OH ) when dissolved in water. 

For example

Sodium hydroxide NaOH (aq), in its aqueous solutions, dissociates as: 

                 NaOH (aq) → Na + (aq) + OH (aq) 

 

Note : The term ‘alkali’ means water soluble bases

 

Some examples of bases are: 

  1. Sodium hydroxide (NaOH) or caustic soda used in washing soaps. 
  2. Potassium hydroxide (KOH) or potash used in bathing soaps. 
  3. Calcium hydroxide (Ca(OH) 2 ) or lime water used in white wash. 
  4. Magnesium hydroxide (Mg(OH) 2 ) or milk of magnesia used to control acidity (it is an antacid). 
  5. Ammonium hydroxide (NH 4 OH) used in hair dyes.

Examples of Bases-Teachoo.jpg

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Properties of Bases:

  1. Bases usually are bitter in taste

  2. Bases can neutralise the effect of acids.

  3. Bases feel soapy to touch

  4. Bases and Indicators

    Indicator

    Color in basic medium

    Litmus Paper

    Red to Blue

    Phenolphthalein

    Colorless

    Methyl orange

    Red

    Turmeric

    Turns from yellow to red .

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  5. Bases conduct electricity in water.

  6. Bases react with some metals to form Hydrogen gas
    Bases + Metal ⎯→ Salt + Hydrogen gas
    Note : All metals do not react with base

  7. Bases react with acids to form salt and water
    Base + Acid ⎯→ Salt + Water

  8. Bases react with non-metal oxides to form salt and water
    Base + Non-metal Oxides ⎯→ Salt + Water
  1. Class 10
  2. Chapter 2 Class 10 - Acids, Bases and Salts (Term 1)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo