How do Acids react with bases?
Let us understand how acids react with bases with the help of an experiment.
Things needed:
- A stand
- A test tube
- Sodium hydroxide
- Phenolphthalein
Procedure:
- Take 2 ml of sodium hydroxide solution in a test-tube.
- Add some drops of phenolphthalein solution to it. The colour of the solution
- Add hydrochloric acid to this solution. The colour of the solution changes
Solution turns pink Solution turns colourless again Observation:
- When phenolphthalein is added to sodium hydroxide, the colour of the solution turns
- When hydrochloric acid is added to the solution, the solution turns colourless
Conclusion:
- The indicator phenolphthalein is colourless in acidic solutions but turns pink in basic solutions. As sodium hydroxide is a base, the indicator turns pink and again turns colourless when acid is
- Thus, the effect of a base is neutralised or nullified by an
Will an acid be neutralised by a base?
Add a few drops of sodium hydroxide back to the above mixture. The pink colour of the phenolphthalein reappears. This is because the effect of acid is neutralised by the base.
Solution turns pink
The reaction taking place in the above experiment is:
𝑵𝒂𝑶𝑯(𝒂𝒒) + 𝑯𝑪𝒍(𝒂𝒒) → 𝑵𝒂𝑪𝒍(𝒂𝒒) + 𝑯𝟐𝑶(𝒍)
Sodium chloride is a salt.
Acids and bases react with each other to give salt and water. This reaction is called a
Neutralisation reaction and can be generalized as
Base + Acid → Salt + Water
Calcium chloride is formed along with water when hydrochloric acid reacts with calcium hydroxide. The reaction taking place is
𝟐𝑯𝑪𝒍 + 𝑪𝒂(𝑶𝑯)𝟐 → 𝑪𝒂𝑪𝒍𝟐 + 𝟐𝑯𝟐𝑶
Formation of Calcium Chloride
During acidity in the stomach, our stomach produces excess hydrochloric acid (HCl). This acid is very harmful to the walls of our stomach as it causes a burning sensation.
To neutralise this acid, antacids are used. Antacids are bases which react with the acid to give salt and water thereby giving relief.
The reaction taking place in the stomach is
Base + HCl → Salt + Water
Reaction of Antacid with Acid