Main Points

Acid Base Salt

  • Acids are substances which are sour in taste and change blue litmus to red.
  • Bases are substances which are bitter in taste, soapy on touch, and change red litmus to blue.
  • A substance which changes its colour in presence of acid or base is called acid-base indicator.
  • When and acid reacts with a metal then a salt and hydrogen gas are formed.
  • When an acid reacts with metal carbonate or metal hydrogen carbonate, then salt, carbon dioxide and water are formed.
  • When an acid reacts with a base then salt and water are formed.
  • When a metallic oxide reacts with an acid then salt and water are formed.
  • When a non-metallic oxide reacts with a base then salt and water are formed.
  • Strength of acidic and basic solutions can be shown by pH scale.
  • The human body works within the pH range of 7.0 to 7.8. Most of the living beings work within this range.
  • Common salt is used as a raw material for making many important chemicals; like bleaching powder, baking soda, caustic soda, etc.

These main points are highly helpful for last minute preparation for examination. You can glance through them while going for examination. You can view them in the school bus, in car, in elevator, etc.