Acids, Bases and Salts
- Acids are those substances which gives H+ inside a solution.
- Ph 1 to Ph 3 are considered as Strong Acids.
- Ph 4 to Ph 6 are considered as weak acids.
- Acidic substances like lemon juice , vinegar etc.. tastes sour.
- Hydrochloric acids, nitric acids are some examples of strong acids.
- Acetic acids, phosphoric acids are some examples of weak acids.
- Bases are those substances which give hydroxide ions( OH-) inside a solution.
- Ph 8 to Ph 14 are considered as bases.
- Ph 8 to 10 are weak bases.
- Ph 11 to 14 are strong bases.
- Bases tastes bitter and are are soapy in nature.
- Sodium hydroxide , calcium hydroxide are some examples of strong bases.
- Ammonia, hydrogen sulphide are some examples of weak bases.
- Substances which are used to identify another substance acidic or basic nature are termed as Indicators.
- Indicators change their colour when exposed to a acid or a base.
- Turmeric, China Rose are some examples of Natural Indicators.
- Litmus is the most commonly used natural indicator.
- It is extracted from Lichens.
- It turns red when added to an acidic solution.
- It turns blue when added to a basic solution.
- The solutions which does not change it’s colour are known as neutral solutions.
- Neutral Solutions have a Ph 7.
- Biological processes on land lead to the formation of harmful gases.
- Acid rain is caused due to sulphuric acid and nitric acid.
- When normal rain falls, these harmful gases get mixed with the rain water and thus forms acid rain.
- Acid rain is also harmful to the health of humans.
- Acid rain can travel longer distances.
- Acid rain is very harmful for buildings, monuments, forests , aquatic life etc..
- The reaction which takes place between acids and bases to give salts and water is known as Neutralisation Reaction.
- For example: when hydrochloric acid is mixed with sodium hydroxide it gives sodium chloride (salt) and water.
- Hydrochloric acid is present on our stomach and it helps in the digestion of our food..
- If we suffer from indigestion then we take antacids such as milk which contain magnesium hydroxide that neutralises the effect of excessive acid.
- Acids of ant bites can be neutralised by rubbing moist baking soda.
- Excessive acids in soil is treated with bases like quick lime or slaked lime.