Table of Contents
- Reaction of Acids with Bases
- What’s Next?
In the previous segment of the chapter ‘Acids, Bases and Salts’, we studied the reaction of acids with metal carbonates and metal hydrocarbonates. In this segment, let us understand the reaction of acids with bases.
How do Acids react with bases?
Let us understand how acids react with bases with the help of an experiment.
- A stand
- A test tube
- Sodium hydroxide
- Take 2 ml of sodium hydroxide solution in a test-tube.
- Add some drops of phenolphthalein solution to it. The colour of the solution changes.
- Add hydrochloric acid to this solution. The colour of the solution changes again.
Solution turns pink Solution turns colourless again Observation:
- When phenolphthalein is added to sodium hydroxide, the colour of the solution turns pink.
- When hydrochloric acid is added to the solution, the solution turns colourless again.
- 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 added.
- Thus, the effect of a base is neutralised or nullified by an acid.
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:
????(??) + ???(??) → ????(??) + ???(?)
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
???? + ??(??)? → ????? + ????