NIOS Class 10 Science and Technology Activity 8.5 Acids, Bases and Salts

This activity demonstrates the neutralisation reaction between an acid and a base with a complete explanation and conclusion.

 

NIOS Class 10 Science and Technology Project File

This activity is based on the NIOS Class 10 Science and Technology chapter 8: Acids, Bases, and Salts.

Aim of the activity

To study the chemical reaction between an acid and a base.

Materials Required

   1. Sodium hydroxide solution

   2. Dilute hydrochloric acid

   3. Phenolphthalein indicator

   4. Test tube

   5.  Dropper

Procedure

We take a clean test tube and pour about 2 mL of sodium hydroxide solution into it. Now we add drops of phenolphthalein indicator using a dropper and observe the changes.

Now we add dilute hydrochloric acid slowly to the above test tube and observe the changes.

Again, we add a few drops of sodium hydroxide in the test tube and observe the change.

Observation

    1. When phenolphthalein is added to a sodium hydroxide solution-  Pinks colour appears

    2. When dilute HCl is added to this solution – Pink colour disappears/fades

    3. When NaOH is added to this solution- Pink colour reappears

Explanation

 Phenolphthalein is a pH indicator that turns pink in basic solution and remains colourless in acidic solution.

The pink colour in NaOH solution shows the basic nature.

When hydrochloric acid is added to a sodium hydroxide solution, they neutralise each other to form salt and water. This is a neutralisation reaction.

NaOH + HCl NaCl + H₂O

When more NaOH is added to the above solution, pink colour reappears, which proves the basic nature.

Conclusion

This activity explains neutralisation reaction in which an acid and a base react to produce salt and water.

Frequently Asked Questions

   1.  Which colour appears when phenolphthalein is added to sodium hydroxide solution?

Answer – Pink colour

   2. Can we use other indicators in this activity?

Answer – Yes, we can also use methyl orange or litmus.

   3. What is the name of the chemical reaction that occurs in this activity?

Answer- Neutralisation reaction