Correct Option
The correct option is (b) 2 only.
Explanation
The passage of an electric current through a conducting liquid (electrolyte) induces chemical reactions. This phenomenon is known as the chemical effect of electric current (electrolysis). The observable effects depend on the nature of the solution and the electrodes used.
Statement-wise Analysis
- Statement 1 is Incorrect. Passing electric current through a conducting solution causes chemical changes, not just physical changes. The process involves the decomposition of the electrolyte into its constituent ions, leading to the formation of new substances.
- Statement 2 is Correct. The formation of gas bubbles on the electrodes is a primary indication of a chemical reaction. For example, passing current through acidified water produces oxygen bubbles at the anode and hydrogen bubbles at the cathode.
- Statement 3 is Incorrect. A change in the colour of the solution is a valid indication of a chemical effect caused by electric current. This color change results from the chemical reactions occurring within the solution.
Key Takeaway: Common manifestations of the chemical effects of electric current include the formation of gas bubbles at electrodes, the deposition of metal on electrodes (electroplating), and changes in the solution's colour.