Materials Required 

• Hydrochloric acid (about 5 mL)
• Sodium hydroxide flakes (about 100 mg)
• Sodium chloride (about 5 g)
• A beaker (250 mL) with water 100mL
• B beaker (250 mL) with water 100mL
• C beaker (250 mL) with water 100mL
• D beaker (250 mL) with water 100mL
• Battery of 6 V with a cell holder
• Torch bulb of 6 V with a torch bulb holder
• Rubber cork
• Two iron nails
• Plug key
• Connecting wires

The Procedure 

Real Lab Procedure

• Take a dry rubber cork and fix two iron nails at a distance. The two nails will work as two electrodes. 
• Observe the circuit diagram before experimenting.

• Take nearly 100 mL of distilled water in the four beakers (250 mL). Label them as beakers A, B, C, and D, respectively.
• Add about five drops of hydrochloric acid in distilled water in beaker A to get an acidic solution.
• Add about 100 mg flakes of sodium hydroxide in beaker B to get a basic solution.
• Add about 2 - 3 g of sodium chloride salt (about half a teaspoon) in water in beaker C to get a sodium chloride salt solution. 
• Do not add anything to the distilled water in beaker D.
• Set up the electric circuit by connecting different components with the help of connecting wires. 
• Do not dip the rubber cork (to which two iron nails are fixed and connected in the circuit) in any beaker.
• Precaution: Remove the key and take out the rubber cork from the beaker. Wash the rubber cork and dry it with a clean cloth before experimenting with different solutions.
• Insert the key into the plug and test the circuit. If the circuit is ON or right, the bulb glows; if the circuit is wrong or OFF, the bulb does not glow.
• Place the rubber cork-connected circuit in beaker A containing dil HCl.
• Insert the key into the plug and allow the current to flow in the circuit containing dil. The hydrochloric acid solution is a component. Take note of the observation. 
• Place the rubber cork-connected circuit in beaker B containing sodium hydroxide solution.
• Insert the key and note down the observation.
• Place the rubber cork-connected circuit in beaker C containing sodium chloride solution.
• Insert the key and note down the observation.
• Place the rubber cork-connected circuit in beaker D containing distilled water.
• Insert the key and note down the observation.

Simulation Procedure

• Drag and drop the dropper containing HCl into the A beaker.
• Drag and drop the watch glass containing 100 mg flakes of sodium hydroxide into the B beaker.
• Drag and drop the watch glass containing 3 g of sodium chloride salt into the C beaker.
• Click on next button.
• To see the circuit diagram, click on the ‘Show circuit diagram’ check box shown inside the simulator window.
• Connections can be made, as seen in the circuit diagram, by clicking and dragging the mouse from one connecting terminal to the other connecting terminal of the devices to be connected.
• Drag and drop iron nails on Rubber cork.
• Drag wire from iron nails and place it on positive terminal of 6v battery.
• Drag wire from 6v negative terminal of battery and place it on 6v bulb with holder.
• Drag wire from 6v bulb and place it on plug key holder.
• Drag wire to iron nails, from plug key.
• Drag and drop plug key on plug key holder.
• Click on next button.
• For beaker A, drag and drop the key into the circuit.
• Click on next button.
• For beaker B, drag and drop the key into the circuit.
• Click on next button.
• For beaker C, drag and drop the key into the circuit.
• Click on next button.
• For beaker D, drag and drop the key into the circuit.
• Click on next button.
• Click on the ‘Reset’ button to redo the experiment.

Observations

Result

Infer from the observations that acids, bases and salts are electrolytes.
Discuss the following dissociation reactions:

HCl (aq) ⎯→ H⁺ (aq) + Cl– (aq)

NaOH (aq) ⎯→ Na⁺ (aq)+OH– (aq)

NaCl (aq) ⎯→ Na⁺ (aq) + Cl– (aq).

Precautions

• The ends of the connecting wires must be cleaned and connected tightly with the other components of the circuit.
• The acidic concentration in the distilled water must be highly diluted. Otherwise, the nails will start reacting with the acid.
• The nails must be partially dipped inside the liquid while performing an electric continuity test.
• The rubber cork must be washed and dried after every test and before dipping it in another liquid solution.