Testing Electrical Conductivity of Different Solutions
Acids, Glucose, and Alcohol
Have you ever wondered why some liquids can conduct electricity while others cannot? This activity from Class 10 Science explores the fascinating property of electrical conductivity in various solutions, including common acids, glucose, and alcohol. We'll discover the underlying reason behind this difference!
Aim of the Activity
To investigate and determine which of the given liquid solutions (dilute acids, glucose solution, and alcohol solution) are capable of conducting electricity.
Materials & Apparatus
- Dilute Hydrochloric Acid (HCl)
- Dilute Sulphuric Acid (H₂SO₄)
- Glucose solution
- Alcohol (Ethanol) solution
- 100 mL Beaker
- Cork (stopper)
- Two iron nails
- Connecting wires
- 6V Battery
- Small electric bulb
- Switch
Procedure
- Prepare the circuit: Take a 100 mL beaker. Fix two iron nails into a cork, ensuring they are separated by a small distance. Place this cork into the beaker.
- Connect the circuit: Connect the two nails to the two terminals of a 6-volt battery through an electric bulb and a switch, forming a complete circuit. (Ensure the nails are submerged in the liquid when added).
- Test with Hydrochloric Acid: Pour some dilute hydrochloric acid into the beaker, ensuring the nails are immersed. Switch on the current and observe whether the bulb glows.
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Repeat with other solutions: Carefully rinse the beaker and nails with distilled water after each test to avoid contamination. Repeat the entire activity (steps 3 and 4) separately with:
- Dilute Sulphuric Acid (H₂SO₄)
- Glucose solution
- Alcohol solution
- Record observations: Note down whether the bulb glows or not for each solution tested.
[Imagine a simple circuit diagram here: 6V Battery → Switch → Bulb → Nail 1 → Solution in Beaker → Nail 2 → Battery]
(A visual representation of the circuit setup would be beneficial here.)
Observation
- The electric bulb glows brightly when testing with both dilute Hydrochloric Acid (HCl) and dilute Sulphuric Acid (H₂SO₄).
- However, the electric bulb does not glow when testing with glucose solution and alcohol solution.
Explanation
The ability of a solution to conduct electricity depends on the presence of mobile charged particles, i.e., ions.
- Acids (HCl, H₂SO₄): When acids like hydrochloric acid and sulphuric acid are dissolved in water, they undergo dissociation to produce hydrogen ions (H⁺) and corresponding anions (e.g., Cl⁻, SO₄²⁻). These free ions act as charge carriers, allowing electricity to flow through the solution, hence the bulb glows.
- Glucose and Alcohol: In contrast, substances like glucose (C₆H₁₂O₆) and alcohol (C₂H₅OH) are covalent compounds. When dissolved in water, they do not dissociate into ions. Although they contain hydrogen atoms, they do not release hydrogen ions in solution. Without free ions, there are no charge carriers, and thus their solutions do not conduct electricity.
Conclusion
From this activity, we can conclude that all acids conduct electricity in aqueous solutions because they produce ions. Conversely, solutions of substances like glucose and alcohol do not conduct electricity as they do not produce ions in water. The flow of electric current through a solution is fundamentally carried by these mobile ions.
Multiple Choice Questions
1. Which solution does NOT conduct electricity?
- a) Glucose
- b) HCl
- c) H₂SO₄
- d) HNO₃
2. Alcohol does not show electrical conductivity because:
- a) Alcohol evaporates
- b) Alcohol has high resistance
- c) Alcohol does not produce ions
- d) None of the above
3. Which of the following solutions is an electrolyte?
- a) Alcohol
- b) Glucose
- c) H₂SO₄
- d) All of the above
Important Precaution
Always handle electrical components and chemicals with extreme care. This experiment should only be performed under the strict supervision and guidance of a qualified teacher or adult. Ensure all connections are secure and avoid contact with the solutions while the circuit is active.