Chemical Properties of Acids and Bases-II

Aim of this experiment is to study the behaviour of acids and bases with litmus papers and conduction of electricity through them. The colour of blue litmus changes to red, while the colour of red litmus remains unaffected in an acidic medium. The colour of red litmus changes to blue, while the colour of blue litmus remains unaffected in a basic medium.

The dilute hydrochloric acid acts as the electrolyte. An electrolyte is an ionic solution that allows the passage of electric current through it.

Apparatus Required

Apparatus and materials required are:

• Blue litmus paper
• Red litmus paper
• Cork
• Stainless steel nails
• Bulb
• Battery
• Connecting wires
• Key
• Dilute HCl
• NaOH solution

Procedure 

The following steps to follow for the procedure:

1. Test the nature of the HCl solution by dipping red and blue litmus papers into it. Record your observations. 
2. Similarly, test the nature of the NaOH solution by dipping red and blue litmus papers into it. Record your observations. 
3. To test the conductivity through acids and bases, take a cork and fix 2 stainless steel nails on it. 
4. Put this cork in an empty beaker. Connect one of the stainless steel nails with the negative terminal of a battery through a connecting wire. 
5. The battery’s positive terminal should be connected to a bulb and a key. Connect the key to the second stainless steel nail fixed on the cork.
6. Pour dilute HCl into the beaker.
7. Switch on the key. Record your observations.
8. Similarly, form another setup to test the conductivity of the NaOH solution and pour the solution into the beaker.
9. Switch on the key and record your observations.

Conclusion

In this experiment, we learned that:

1. The blue litmus paper turns red, but the red litmus paper remains unaffected in an acidic medium. 
2. The red litmus paper turns blue, but the blue litmus paper remains unaffected in a basic medium. 
3. Acids conduct electric current in an aqueous medium due to the presence of H+ ions and the respective anions.
4. Bases conduct electric current in an aqueous medium due to OH- ions and the respective cations.

FAQs on Chemical Properties of Acids and Bases