Question

With the help of labelled diagrams, describe an activity to show that acids produce ions only in aqueous solutions.

Answer 1

Procedure:

• Take about 1 g of sodium chloride (NaCl) in a clean and dry test tube.
• Add some concentrated sulphuric acid (H₂SO₄).
• A gas is produced and comes out through the delivery tube.
• Test the gas evolved with dry and wet strips of litmus paper.

Observation:
(i) When the gas evolved is passed through dry litmus paper, there is no change in the colour of litmus paper.
(ii) However, when the gas is passed through wet blue litmus paper, the paper turns red, which indicates that the gas evolved is an acid, HCl.

Conclusion:
This activity concludes that hydrogen ions in HCl are produced in the presence of water because only wet blue litmus turns red.