Question 25 of 34intermediate🔧 ApplyLong Answer5 marks

Compounds such as alcohols and glucose also contain hydrogen but are not categorised as acids. Describe an Activity to prove it.

Correct Answer

Activity to show that glucose and alcohol are not acids:

Materials Required: Solutions of glucose, alcohol, hydrochloric acid, sulphuric acid, a 100 mL beaker, cork with two nails fixed, 6 volt battery, bulb, switch and connecting wires.

Procedure: Fix two nails on a cork and place it in a 100 mL beaker. Connect the nails to the two terminals of a 6 volt battery through a bulb and a switch. Pour dilute HCl in the beaker and switch on the current. Observe whether the bulb glows. Repeat the same experiment with dilute sulphuric acid. Now, repeat the experiment separately with glucose and alcohol solutions.

Observations: The bulb glows when HCl or sulphuric acid is used. However, the bulb does not glow when glucose or alcohol solutions are used.

Conclusion: The glowing of the bulb indicates flow of electric current through the solution. The electric current is carried through the acidic solution by ions. Acids produce hydrogen ions, H+(aq) in solution, which are responsible for their acidic properties. Since glucose and alcohol solutions do not conduct electricity, they do not produce H+ ions in solution. Hence, even though they contain hydrogen, they are not categorised as acids.

Exercise: EXERCISES | Q: 6 | (Page Page 18)
For More Understanding

Explanation

This activity (Activity 2.8 from the textbook) demonstrates the fundamental difference between acids and compounds like glucose and alcohol. The key concept is that acids dissociate in aqueous solution to produce H+ ions, which are responsible for conductivity and acidic properties. Glucose and alcohol contain hydrogen atoms, but these are not released as H+ ions in solution, hence they cannot conduct electricity and are not classified as acids.

Solution Steps

  1. Step 1: Set up the apparatus with cork, nails, beaker, battery, bulb and switch.

  2. Step 2: Test with acids (HCl, H2SO4) - observe bulb glowing.

  3. Step 3: Test with glucose and alcohol solutions - observe bulb NOT glowing.

  4. Step 4: Conclude that acids produce H+ ions (conduct electricity) while glucose/alcohol do not.

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