Explanation :
The imbalance of the electric charge is called static electricity. When objects are rubbed against each other, one object loose electron while the other one gains an electron.
This creates a disturbance in the charge. But the overall charge remains constant.
The law of conservation of charge states that :
The charge neither is created nor be destroyed i.e. the net charge always remains conserved.
Hence, the static electricity illustrates the Law of conservation of charge.