Which of the following is/are chemical effect(s) of electric current when it passes through a conducting solution?

All of these

The correct answer is option 4. All of these.

The passage of an electric current through a conducting solution causes chemical reactions.

As a result, there are some of the chemical effects of the electric current.

(i) Bubbles of a gas may be formed on the electrodes.

(ii) Deposits of metal may be seen on electrodes. 

(iii) Changes of colour of solutions may occur.

The reaction would depend on what solution and electrodes are used.