2. Acids, Bases and Salts SCIENCE class 10 in English Medium ncert book solutions Chapter Review

Chapter Review:

• There are some substances whose odour changes in acidic or basic media. These are called olfactory indicators.
• Vanilla, onion and clove, can be used as olfactory indicators.
• The metal combines with the remaining part of the acid and forms a compound called a salt.
• Limestone, chalk and marble are different forms of calcium carbonate.
• The reaction between an acid and a base to give a salt and water is
  known as a neutralisation reaction.
• Metallic oxides react with acids to give salts and water, similar to the
  reaction of a base with an acid, metallic oxides are said to be basic oxides.
• All acids produce hydrogen ions, H+(aq), in solution.
• All bases produce OH–(aq), in solution.
• The pH of a neutral solution is 7.
• Values less than 7 on the pH scale represent an acidic solution.
• PH of rain water is less than 5.6, it is called acid rain.
• Tooth decay starts when the pH of the mouth is lower than 5.5.
• Salts of a strong acid and a strong base are neutral with pH value of 7.
• The salt formed by the combination of hydrochloric acid and
  sodium hydroxide solution is called sodium chloride.
• Deposits of solid salt are also found in several parts of the world. These large crystals are often brown due to impurities. This is
  called rock salt
• When electricity is passed through an aqueous solution of sodium
  chloride (called brine).
• The baking soda commonly used in the kitchen for making tasty crispy pakoras.
• On heating gypsum at 373 K, it loses water molecules and becomes
  calcium sulphate hemihydrate. This is called Plaster of Paris.