Chapter 8: Acids and Alkalis

Acids


Properties of acids:
   >  Tastes sour
   > Reacts with metals to produce hydrogen gas
      - Test for hydrogen gas: Hydrogen gas extinguishes a lighted wooden splint with a "pop" sound.

      - Examples of Writing word equations for the chemical reactions of acids and metals:

         ~ Sulfuric acid + Zinc ---> Zinc Sulfate + Hydrogen gas

         ~ Hydrochloric acid + Zinc ---> Zinc chloride + Hydrogen gas

         ~ Nitric acid + Zinc ---> Zinc nitrate + Hydrogen gas

   > Reacts with carbonates to produce carbon dioxide gas and water

      - Test for carbon dioxide: forms white precipitate in lime water
      - Examples of Writing word equations for the chemical reactions of acids and metal carbonates:

         ~ Sulfuric acid + Zinc carbonate ---> Zinc Sulfate + Carbon dioxide gas + water

         ~ Hydrochloric acid + Zinc carbonate ---> Zinc chloride + Carbon dioxide gas + water

         ~ Nitric acid + Zinc carbonate ---> Zinc nitrate + Carbon dioxide gas + water

   > Test for acids: Turns red litmus paper red/ turns blue litmus paper red
   > Has a pH level lower than 7


Alkalis


Properties of alkalis:
   > Tastes bitter
   > Has a soapy feel
   > Test for alkalis: Turns red litmus paper blue/ Turns blue litmus paper blue
   > Has a pH level higher the 7


Neutralization of acids and alkalis


Neutralization is a reaction that occurs when acids and alkalis are mixed together. Salt and water will be produce in this reaction. Some examples of Neutralization in our daily lives: Usage of shampoo(alkaline) and conditioners(slightly acidic) and usage of toothpaste(alkaline) on our teeth(acidic).


Indicators


Indicators indicates if the substance is acidic or alkaline or the pH level of the substance. For instance, the blue & red litmus paper, methyl orange, phenolphthalein and the universal indicator. The acidic or alkaline level of a solution is known through its pH level through a scale of colors or a scale of numbers which ranges from 0 to 14.Indicators indicates if the substance is acidic or alkaline or the pH level of the substance. For instance, the blue & red litmus paper, methyl orange, phenolphthalein and the universal indicator. The acidic or alkaline level of a solution is known through its pH level through a scale of colors or a scale of numbers which ranges from 0 to 14.

the universal indicator

a pH scale of colors

Source: google images