> he made nickel counting electrode and he need to put it all inside 4M NaOH solution. He is concerned that the alligator clip can tolerate NaOH solution or not
This is a very strange question. Maybe I am misunderstanding your question.
Nobody puts the crocodile clip into the solution because the crocodile clip is applying the voltage, so if it is in contact with the solution, it will conduct electricity through the solution instead of the electrode, and there is no point having the electrode there!
it is normal to connect the electrode cable crocodile clip to the electrode, put the electrode into the solution, and make sure the crocodile clip doesn’t touch the solution.
The electrode cable crocodile clip will tolerate the 4M NaOH solution if it is connected to the electrode, and only the electrode is put into the 4M NaOH solution.