NIOS Class 10 Science and Technology Activity 7.1 Chemical Bonding

This activity demonstrates the electrical conductivity of ionic compounds in aqueous solution.

 

NIOS Class 10 Science and Technology Project File

This activity is based on the NIOS Class 10 Science and Technology chapter 7, Chemical Bonding.

Aim of the activity

To test the electrical conductivity of an aqueous solution of sodium chloride

Materials Required

    1. Table salt (NaCl)

    2. Distilled water

    3. Two graphite electrodes

    4.      200 mL beaker

    5.      3 V dry cell

    6. Connecting wires

    7. Electrical bulb

    8. Switch

Procedure

We take 100 mL of distilled water in a 200 mL beaker. Now we dip two graphite electrodes in it and connect them to a 3 V battery, bulb, and switch with wires. We observe the bulb with plain distilled water.

Now we prepare a solution by dissolving 1 tablespoon of table salt in 100 mL of distilled water.

Now we replace the plain distilled water with this salt solution and observe the bulb again.

Observation

    1.  The bulb does not glow or glows very dimly with plain distilled water.

    2. The bulb glows with salt solution.

Explanation

Distilled water does not contain free ions and does not conduct electricity.

Sodium chloride is an ionic compound that, when dissolved in water, dissociates into Na⁺ and Cl^- ions.

These free ions carry an electric current through the solution, and thus the bulb glows.

Conclusion

This activity explains that an aqueous solution of ionic compounds conducts an electric current due to the presence of free ions.

Frequently Asked Questions

    1. Why doesn’t the bulb glow in plain water?

Answer – Because plain or pure water does not have free ions to conduct electricity.

    2. What type of bond is present in NaCl?

Answer- Ionic bond

  

   3. Do all salts conduct electricity when dissolved in water?

Answer – Yes, most ionic salts conduct electricity when dissolved in water. This also depends on the solubility of salts in water.