Examples of Neutral Substances

According to your acidity level, substances are classified as acidic, alkaline or neutral. Acidity is measured in pH units. The pH (potential of hydrogen) is used to measure the acidity or alkalinity of a substance in aqueous solution. The pH range established under normal pressure and temperature conditions ranges from 0 to 14, with a pH = 7 for a neutral substance.

Substances whose pH is equal to or very close to 7 are called neutral substances. For example: the pH of blood is between 7.3 and 7.4 and that of saliva is between 6.5 and 7.4.

Substances whose pH is less than 7 are acidic substances. Acidity means that the concentration of positively charged hydrogen ions (H+ or [H3O]+) is greater than that of hydroxyl ions (OH) negatively charged.

Substances whose pH is greater than 7 are alkaline. The higher level alkalinity under normal conditions it is pH = 14. A substance is alkaline when the concentration of hydroxyl ions (OH) negatively charged is greater than that of positively charged hydrogen ions.

Some characteristics of neutral substances:

  • They do not cause changes in acid-base indicators (eg litmus paper or phenolphthalein).
  • They are not usually corrosive.
  • In a neutral solution the concentration of ions H+ and OH it’s the same.

Some characteristics of acids:

  • Its taste is sour.
  • They redden the litmus paper.
  • They produce effervescence with calcium carbonate.
  • They react with some metals such as zinc or iron.
  • They neutralize the bases.
  • In aqueous solution they facilitate the passage of electric current.
  • They are corrosive to biological tissues such as the skin.
  • They dissolve many substances.

Some characteristics of the bases (or alkaline compounds):

  • Its taste is bitter.
  • They tile the litmus paper.
  • They are unctuous to the touch.
  • Substances that have been dissolved by acids precipitate.
  • In aqueous solution they also facilitate the passage of electric current.
  • They dissolve fats and sulfur dioxide (SOtwo).
  • They neutralize acids.

Examples of neutral substances

  1. Milk. It is a neutral substance (pH 6.5). However, when it comes into contact with gastric juices it stimulates the decrease in stomach pH so, contrary to what is usually believed, it is not recommended to consume it when you suffer from heartburn.
  2. Running water. Tap water or tap water must be a neutral substance. However, on certain occasions water can be ionized, that is, its hydrogen ions can increase (positively charged), which causes the water to become acidic.
  3. Soda. Minerals and gas (COtwo) of bottled water do not change its pH significantly.
  4. Mineral water without gas. It is a type of water that has minerals but no carbon dioxide. Likewise, its pH does not vary appreciably.
  5. Liquid soap. The skin is an acid medium (pH 5.5 approximately), while solid soaps have a pH greater than 8. Liquid soaps are synthetic products to which acidic substances are added to achieve a neutral pH. Glycerin soap is said to be “neutral” because it has a pH similar to that of skin, but chemically speaking it is an acidic substance since its pH is less than 7.
  6. Liquid laundry soap. Neutral soap is less aggressive with textile fabrics than acid soaps.
  7. Blood. Its pH is between 7.3 and 7.4.
  8. Saliva. Its pH is between 6.5 and 7.4.